US3097472A

US3097472A - Apparatus for making rope strand

Info

Publication number: US3097472A
Authority: US
Publication date: 1963-07-16
Anticipated expiration: 1980-07-16

Description

July 16, 1963 J. STIRLING Filed July 16, 1959 FIG.2

APPARATUS FOR MAKING ROPE STRAND 4 Sheets-Sheet l 4 16C zsaa-H- 2 5 160 24A 30 $1 1sB 58 59 all 20 INVENTOIF.

James Shrlmg BY am /3' 5 m ATTORNEY J. STIRLING 3,097,472

APPARATUS FUR MAKING ROPE. STRAND July 16, 1963 4 Sheets-Sheet 2 Filed July 16, 1959 FIG. 5

r 60A --l 6 r l 6 TO CAPSTAN INVENTOR. James Srirling ATTORNEY July 16, 1963 J. STIRLING 3,097,472

APPARATUS FOR MAKING ROPE STRAND Filed July 16, 1959 4 Sheets-Sheet 3 INVENTOR. James Srirling ATTORNEY July 16, 1963 J. STIRLING 3,097,472

' APPARATUS FOR MAKING ROPE STRAND Filed July 16, 1959 4 Sheets-Sheet 4 INVENTOR. James Srirling ATTORNEY United States Patent 33391472 APPARATUS FOR MAKHNG RGPE STRAND James Stirling, 109-26 Zilfith Sn, Queens Village, N.Y. Filed July 16, 1959, Ser. No. 827,515 3 Claims. (or. 57-15 This invention relates in general to an apparatus for making rope, and more specifically to a machine for making an improved strand of rope in which each fibre or end in the rope strand is made substantially equal in length and thereby assures that each of the strand fibres or ends are uniformly stressed under a given load condition.

It has been observed upon rnany examinations that ropes of conventional construction fail for the most part in one strand which is broken to destruction while the other strands usually have several of the inside or core yarns pulled out to destruction and the cover yarns showing no signs of appreciable damage. The extent of the damage resulting from such breaks of course depend on the specific construction of the rope with regard to the twist of the yarn, the lay of the strand, the lay of the rope, the fore-hard and the tension during manufacture, but the indications are evident that the load has been unevenly distributed over each strand and over each of the individual ends or yarns therein.

In considering for example a three strand manila rope of 5" circumference, such rope normally requires 50 ends or fibres of #18 yarn (270 ft./lb.) in each strand. If 290 lbs. is taken as the breaking strain for this size yarn, it will be noted that 3 strands 50 ends X290 lbs. per end equals 43,500 lbs., or the theoretical breaking strain for such rope. However, the required minimum break for such 5 circumference 3 strand manila rope according .to Federal Specification "TR-60S is 22,500 lbs. or approximately 48% less than the 43,500 lbs. These facts are well known to rope-makers, but with the exception of some recent methods to vary the twist and yarn sizes for the core yarns, very little has been done to reduce this loss in strength.

A further examination of a piece of finished 5 circumference manila rope of standard lay and conventional construction will reveal that the individual y-arns in the strand vary in length over the length of the finished rope approximately as follows:

The outside cove-r yarns, plus 32.3%; The second cover yarns, plus 26.2%; The core cover yarns, plus 24.1%; and The core yarns, plus 23%.

As a result of the variance in the lengths of the yarns in the respective layer of a rope strand, the maximum pull on the strand is taken by the inside or core yarn when a load is applied to the strand.

The above percentages of length of course will vary with the diiierent materials used, but in all cases where the rope strand is made in accordance with known constructions, there will be a considerable variance in the length of the fibres in the respective layers of the strand, i.e. the cover yarns will be longer than the core yarns. Usually a piece of such rope broken in a test machine will break in one strand. Examination of the remaining unbroken strands will show several of the core yarns broken int-o short powdery lengths while the cover yarns show very little sign of damage, indicating that the core yarns, being shorter, are carrying more than their share of the load.

Therefore, an object of this invention is to provide a rope construction in which the lengths of the individual yarns, cords, or ends used in a rope strand are rendered substantially equal in length so that each yarn will be uniformly stressed under a given load condition.

Another object is to provide an apparatus tor control- "ice ling and varying the twist of the respective layers of yarn making up a strand of rope so as to assure that the lengths of the individual yarns in each of the layers are made substantially equal in length.

Another object is to provide a rope making machine which controls the pitch at which the fibres are twisted per unit length of rope whereby the twist of the respective layers of fibres from the core to the outermost layer of the strand is progressively decreased so that in a finished strand the respective fibres of the core and of each of the succeeding layers are substantially equal in length for insuring uniform stressing of the respective fibres under given load conditions.

Still another object of the invention is to provide a machine in which the loss in strength of all types of ropes of either natural or man-made fibres made thereby is reduced to a minimum.

Still another object is to provide an apparatus for making an improved strand of rope that is relatively simple in construction, relatively inexpensive to fabricate and positive in operation.

A further object is to provide a machine for achieving a balanced rope strand construction.

The foregoing objects are attained by a machine capable of producing a strand of rope in which the respective ends, yarns or cords making up the rope strand are maintained substantially equal in length per unit length of finished strand so as to result in each end or cord being able to take its equal share of the load when applied thereto, either for obtaining maximum break or for achieving maximum service at whatever load applied. In general the machine com-prises a plurality of bobbin carrying table units journaled in spaced relationship to a hollow shafting means, each table unit being independently driven at varying relative rotational speeds. Accordingly, the respective table units may be governed by suitable change gears or the like so that the relative angular rotation of the respective table units maybe changed at will. The arrangement is such that one table unit is provided for each and every layer making up the rope strand, i.e. one table unit is provided for the core yarns and one table unit each for every layer of yarn out to and including the cover yarns. Thus, for a three layer strand three tables can be used, and for a four layer rope strand four tables can be used, and

so on.

In accordance with this invention means are provided for independently controlling and varying the revolutions of the respective tables with respect to one another so as to give the correct number of turns or twist to each of the respective yarn layers. so that in the finished strand each of the ends or yarn are substantially equal in length. As a consequence the finished strand would come very close to having each end assume an equal share of the load applied thereto. If desired the respective table units may be rotated in the same direction, or in opposite directions.

A feature of this invention resides in the provision wherein the respective bobbin carrying table units are independently controlled to vary the twist of the fibres or ends accordingly in the respective fibre layers making up a rope strand so that the respective lengths of the fibres in a unit length of the finished strand are substantially equal in length.

Other features and advantages will become more readily apparent when considered in view of the drawings in which:

FIG. 1 shows the general arrangement of the rope making machine, shown partly in section, embodying the instanit invention in which three bobbin carrying tables are use FIG. 2 shows a view of a piece of three strand rope with one strand marked off to show the general pattern of the individual cover yarns.

FIG. 3 shows an enlarged cross section of the rope taken along line 33 of FIG. 2, and illustrates the different layers of yarn from the outside cover yarns to the core arns.

y FIG. 4 shows a piece of rope with yarns or ends removed to show the core of the strand; the cover yarns for the core; and the outside cover yarns. P1, P2 and P3 show the pitch or lay to illustrate the increase in the twist per foot of the progressive layers towards the core to balance the lengths of all the yarns when the strand is layed into the finished rope.

FIG. 5 shows a modified construction for a machine that would be more practical inasmuch as the bobbins for the core yarns are carried on the top table, and the core is pulled through hollow shafting all the way down to the finished strand. Again only three tables are shown but the number of tables would be controlled by the capacity of the machine desired.

FIG. 6 shows a plan view of tap table taken along line 66 of FIG. 5.

' FIG. 7 shows the drive means for the individual tables through spur gear trains adapted for use with the machine of either FIGS. 1 or 5.

FIG. 8 is a side elevation view of a modified embodiment utilizing four bobbin tables.

FIG. 9 is a rear elevation view of the machine of FIG. 8.

Referring to the drawings, FIG. 2 illustrates a length of an improved rope construction 10 having three

strands

10A, 10B, 10C which are produced on the machine of this invention. The rope 10 is illustrated with one strand 10B marked off to show the general pattern of the individual cover yarns. One of the outside cover yarns is shaded darker to illustrate how it shows up on the outside and travels in a spiral around the outside of the strand going to the inside of the rope and reappearing on the outside again in a distance approximately equal to the lay of the rope. As shown in FIG. 3, the cross section of the rope illustrates the different layers of yarn in each of the

strands

10A, 10B and 10C from the outside cover yarns 100 to the core yarns 10a. In the illustrated embodiment three layers of yarn or fibres make up the

respective strands

10A, 10B, 10C.

FIG. 4 illustrates a detail of one of the strands, e.g. strand 10A, making up the rope 10 of FIG. 2. Portions of the yarns or ends are removed to show the core layer 10a of the strand, the cover yarns 10b 'for the core 10a, and the outside cover yarns 10c. P1, P2 and P3 illustrate the pitch or lay of the yarns in the

respective layers

10a, 10b, 100 which make up the strand, and thus shows the increase in the twist per foot of the progressive layers towards the core to balance the respective lengths of all the yarns when the strand is layed into the finished rope.

In accordance with this invention the rope strand 10A of FIG. 4 is made by a machine illustrated in FIG. 1. In the embodiment of FIG. 1, the frame of the machine is not shown. The machine of FIG. 1 in essence comprises a plurality of bobbin carrying

table units

16, 17 and 18 journaled to a hollow shafting means 19 in spaced relationship. Each of the

table units

16, 17, 18 comprises spaced upper and

lower plates

16A, 16B; 17A, 17B; 18A, 18B; respectively arranged to carry therebetween a plurality of bobbins or spools 16C, 17C, 18C, respectively, for supplying the

yarn

16D, 17D, 18D for the

respective layers

10a, 10b, 100 of the strand 10A.

In the form of the invention of FIG. 1, three table units are shown. The bottommost table unit 16 carries the bobbins 16C supplying the core yarn 16D. The middle table unit 17 carries the bobbins 17C supplying yarn 17D for the core cover yarn or second layer 1011, and the top table unit 18 carries the bobbins 18C supplying the yarn 18D for the outermost layer 100. However, it will be understood that the number of table units can be varied in accordance with the number of layers required in a strand of given size.

In accordance with this invention a hollow shafting means 19 maintains the respective table units in coaxial spaced relationship and it comprises a plurality of axially aligned, rotatably journaled

shafts

19A, 13B, and 19C, and at

least shafts

19B, 19C being hollow or having a bore extending therethrough. The lowermost shaft 19A is rotatably journaled in a bearing enclosed in the lower flanged bearing housing 20. Keyed to the shaft 19A is a bevel gear 21, and if desired a suitable sleeve spacer 22 may be interposed between the flanged housing 26 and the bevel gear 21. The shaft 19 also has keyed thereto a table support 23 to which lower plate 16B of the lowermost table unit 16 is connected. The upper table support 24 which supports the upper plate 16A of the lowermost table unit 16 is also keyed to shaft 19A. The upper table support 24 is provided with a series of aligned

holes

25, 26 in the

flanges

24A, 24B, respectively thereof to function as guide holes for the respective yarns 16D taken off spools 16C, the ends of the yarns being extended through the bore of the next succeeding shaft 19B.

Connected to the upper plate 16A of table unit 16 is a coupler 27 to which the hollow shaft 193 of the middle table unit 17 is rotatably journaled. Accordingly, the coupler 27 rotates in a bearing mounted to a machine frame member 28 with the table unit 16. This is attained by a combination of four spacers and bolt assemblies 29 which connect the coupler 27 to the plate 16A of table unit 16. The upper portion 29A of the spacer-bolt combination 29 serves as a spacer to join the flange 27A of coupler 27 to plate 16A of table unit 16; and the lower portion 29B forms a through bolt which carries a cylindrical sleeve 30 spacing plate 16A from plate 16B of the table unit '16. Y

The hollow shaft 19B of the middle table unit 17 rests on a thrust bearing and rotates in a bearing in coupler 27. Keyed to hollow shaft 19B is a bevel gear 31. Also keyed to shaft 19B are the lower and

upper supports

33, 34, respectively, of the

plates

17A and 17B of the middle table unit 17. A sleeve spacer 32C is interposed between bevel gear 31 and coupler 27. The middle table unit 17 carries the spools 17C containing the yarn 17D for the core cover layer, the upper table supports 34 having aligned openings 35, 36 in

flanges

34A, 34B, respectively, to serve as guides for the respective yarns taken from spools 17C and which are threaded through the bore of shaft 19C. To compact the yarn into desired shape, a compacting tube 32 is disposed in coupler 27 and is aligned with the bore of shaft 138. Tube 32 is held in place by set screw 32A.

The hollow shaft 19C of the upper table unit It; is connected to the upper plate 17A of table unit 17 by a coupler 37 and combination bolts 39 in a manner previously described. Keyed to hollow shaft 19C is a bevel gear 41 and the lower and upper table supports 43, 44 of table u-nit plates 18B and 18A respectively.

Spacer sleeves

44A, 44B space the respective plates 18A, 18B of table unit 18, the respective flanges of which being provided with guide holes for the yarn 18D supplied by spools 18C carried by the upper table unit 18. Coupler 37 also has fitted thereto a compacting tube 32. The purpose of tubes 32, 32' is to compact the yarn or end passing therethrough to insure the desired firmness or compactness of the respective yarn in the finished strand.

From the foregoing description it will be noted that the core yarns 16D from spools 16C extend centrally through shafts 13B and 19C. The yarn 17D for the core cover layer 10b extends through shaft so as to be concentrically twisted about the core yarns 16D, and the cover yarns 18D are twisted concentrically about the core cover yarns 17D, upon the relative rotation of the respective table units 16, =17 and 18.

In accordance with this invention each of the

table units

16, 17, 18 are individually rotated at variable relative angular speeds. Referring particularly to FIG. 7, this is attained by a drive shaft 50 driven by a suitable power means, e.g. an electric motor (not shown in FIG. 7). A worm 51 is carried on the drive shaft or motor spindle 50 and it is arranged to mesh with a worm gear 52. The shaft 53 of the worm gear 52 connects with complementary miter gears 54 arranged to drive a vertically disposed driven shaft 55. Vertically spaced along the driven shaft 55 and fixed thereto are several bevel gears 56, one for each

table unit

16, 17, 18 of the machine. In FIG. 7, only two of the bevel gears 56 are shown on shaft 55.

Each of the bevel gears 56 on driven shaft 55 drives a compound gear train 57, of which only one gear train 57 is shown in FIG. 7. The shaft 58 from spur gear 57A of the gear train 57 has keyed thereto a miter gear 59 which is adapted to mesh with bevel gear 21 fixed to the shaft 19A of the lower table unit 17 of FIG. 1. Each of the respective gear train shafts 58B and 580 will effect rotation of the other table units 17 and 13. Thus it will be apparent that by the drive means described the power of the motor is transmitted to the

respective shafts

19A, 19B, 19C of the respective table unit, and thereby effect relative rotation of the respective table units connected thereto in accordance with the speed ratios of the respective gear trains 57.

In accordance with this invention each of the gear trains 57, of which only one is shown, is provided with suitable gear ratios so that the speed and direction of rotation of the respective table units can be individually controlled and established. Thus the relative angular speed of the

respective table units

16, 17, 18 attains a result in which the ends or yarns in a finished strand are maintained substantially uniform or equal in length.

If desired gears of the respective gear trains may include a change gear which can be readily interchanged so as to vary the angular speeds of a given table unit controlled thereby at will. Therefore, from the foregoing description it will be readily apparent that the twist, i.e. number of turns per given unit length of the respective rope layers will vary in accordance with the relative angular rotation of the

respective table units

16, 17, 18. In the illustrated embodiment the ratios of the gear trains are calculated so that the pitch of the respective layers increase progressively from the core to the outermost cover layer, as best seen in FIG. 4, i.e. twist per unit length of the respective layers of yarn from the core to the outermost layer of the strand is progressively decreased so that in the finished strand the individual yarn of the respective layers are substantially equal in length, and thereby each yarn is able to carry substantially its equal share of the load when stressed.

FIG. 5 illustrates a slightly modified form of the invention. The structure of FIG. 5 is essentially similar to that described with reference to FIG. 1, with the exception that the

table units

60, 61 and 62 are arranged so that the table unit 60 carrying the core yarn 60A on spools 60B is positioned at the top of the column, and the outermost layer of yarn 62A is taken from spools 62B carried by the lowermost table unit 62. In effect then the embodiment of FIG. 5 including the

table units

60, 61, 62, land the shaft means 63 including the couplers 64 and bolt assemblies 65 are the same as that of FIG. 1, but inverted. A drive means similar to that described with reference to FIG. 7 is utilized to drive the

respective table units

60, 61, 62 of FIG. 5 through

shafts

58, 58B and 580, it being understood that the gear ratios 57 driving

shafts

58, 58B, 58C are selected to attain the end desired as hereinbefore described.

FIGS. 8 and 9 illustrate an embodiment employing a modified drive means. As shown therein the machine 70 comprises a base 71 for supporting a frame 72, which is formed of suitable structural members. The frame 72 comprises essentially rectangularly disposed uprights 73 interconnected by horizontally disposed cross braces 74. In this form of the invention four

table units

75, 76, 77 and 78 are supported in a column on the frame 72,

thus signifying that a four layer rope strand 79' is formed thereby. The table units 75 to 78 are each maintained in coaXi-ally spaced relationship by a hollow shafting means 80 and the assembly thereof is similar in every respect to the construction herein described with reference to FIG. 1, with the exception that another table unit and its associated shaft has been added. For this reason a further description of the specific table unit assembly is not deemed necessary for an understanding of the invention.

Supported on the frame 72 is a capstan means 81 and capstan drive means 82 for taking up the finished strand of rope 79 as it is being formed. As shown the finished strand of rope 79 is threaded over an idler pulley 83 mounted on the top of the frame, then over a pair of smaller idlers 84 to lead the finished strand to the driven capstan mean-s 81 about which the strand is. wound several times. From the capstan means 81 the rope strand is threaded over a take-off pulley 85 from whence it is diverted to a take-up reel, not shown.

In accordance with this. form of the invention the capstan means 81 is driven at a relative speed with respect to the relative angular speeds of the respective table units. As shown, each of the table units 75 to 78 and the capstan means 81 are driven by a single source of power, e.g. an electric motor 86.

Accordingly a series of horizontally disposed driving

shafts

87, 38, 39, and are rotatably journaled on the frame 72, each shaft forming a drive for one of the

table units

75, 76, 77 and 78, respectively. Each shaft 87 to 90 has connected thereto at one end thereof a

bevel gear

87A, 88A, 89A, 90A arranged to mesh with a

complementary gear

87B, 88B, 89B, 90B keyed to the shaft means 80 to which each of the respective table units is connected. Each of the shafts 87 to 90 in turn is adapted to be driven off the power source 86.

This is attained by the motor spindle 91 having connected thereto a worm 92 arranged to mesh with a worm gear 93. The shaft 94 of the worm gear 93 in turn is connected to complementary miter gears 95, 95A one of which 95A is keyed to shaft 87 for driving the lowermost table unit 75.

Shaft 87 in turn is connected in driving relationship with the drive shaft 88 of the next superposed table unit 76 by a flexible or chain drive 96. As shown, each of the

shafts

87 and 88 have connected thereto a

sprocket

97, 98, respectively, over which the chain 96 of the drive is threaded. Accordingly, it will be noted that each of the succeeding

shafts

89, 90 are in turn driven by a

chain drive

99, 100 receiving its driving force from the next preceding drive shaft of the column of table units; it being observed that the

intermediate shafts

88, 89 have keyed thereto a

double sprocket

98 and 101, respectively. In order that each of the

respective table units

75, 76, 77, 78 may be rotated at relative angular speeds with respect to one another so as to attain the relative twist desired in each of the respective layers of the rope strand, each of the

sprockets

97, 98, 101, 102 is sized so as to establish the calculated relative angular speeds necessary to attain the end result herein described. If desired suitable chain tensioning means 103, as shown, may be provided. Such means comprise a pivotally adjustable arm 103A having an idler 103B rotatably connected thereto, and it is disposed in rolling engagement with its respective drive chain.

The drive of the capstan means 81 in turn is taken off the uppermost drive shaft 90. As shown in FIGS. 8 and 9 the end of the drive shaft 90 has connected thereto a miter .gear 104 which meshes with a bevel gear 105 journaled to the drive shaft 106 of the capstan means 81. The drive shaft 106 in turn is connected to a gear train 107 which in turn effects rotation of a driven capstan shaft 108, the latter having connected thereto a spur gear 109 meshing with the

respective gears

110, 111 journaled to each of the capstan take-up rolls 110A, 111A. Thus by the appropriate selection of gear ratios 7 107 the speed of the capstan means 81 can be controlled so 'as to have a predetermined angular speed with respect to the relative angular speeds of the respective individual table units. In order to vary the speed of the capstan drive 82 the capstan gear train 107 may include a change gear that can be readily interchanged with another and thereby vary its speed ratio accordingly so as to obtain any desired lay of the strand.

From the foregoing it will be noted that the method of making an improved strand of rope in accordance with this invention comprises the steps of progressively twisting a plurality of threads, cords or ends to form a core layer with a predetermined pitch or number of turns per unit length, and successive twisting of a plurality of other cords or ends concentrically about the core layer so that the pitch of the core cover layer is greater than that of the core layer so that in a finished strand of unit length the cord or ends of the respective layers are substantially equal in length whereby each end :may be uniformly stressed when a load is applied thereto. In accordance with this method two or more layers of fibers may be concentrically twisted one layer upon the other wherein the twist or number of turns per unit length of the succeeding layers from the outermost layer to the core layer is progressively increased. Also, it is contemplated that the respective layers may be twisted either in the same direction or opposite direction. It is also noted that the method described is equally applicable to making rope strand of synthetic fibres, as well as of natural fibres.

The machine constructions as disclosed in FIGS. 1 and 5, wherein the strand is formed through hollow shafting means extending either vertically upwardly or vertically downwardly, are not intended to be so limited for the making of rope strands of balanced construction described herein. It will be readily apparent that the balance rope construction can be made with equal facility on a machine construction in which the respective table units are journaled to a horizontally disposed shafting means so that the rope strand may be pulled horizontally therethrough. Also it is to be appreciated that yarn or ends for forming the final cover layer may be taken from spools held on a creel. In such instances the final cover yarn would be twisted onto a strand, otherwise formed in accordance with this invention, by the rotation of a fiyer as in conventional rope-making equipment; it being of course understood that the respective table units have imparted thereto an individual directional rotation and speed ratio relative to one another and to that of the flyer so as to attain the results herein described.

While the instant invention has been disclosed with reference to given embodiments thereof, it is to be appreciated that the invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention.

What is claimed is:

1. A machine for making rope strand from a plurality of either natural and/or synthetic fibres, comprising a plurality of tables, hollow shafting means connecting said tables in co-axially spaced relationship, each of said tables being rotatably journaled with said shafting means, a plurality of bobbins having fibre windings thereon mounted on each of said tables, the bobbins mounted on each of said tables being radially spaced about said hollow shafting means, means for drawing the fibres from the respective bobbins of each table through the hollow shafting means, means for rotating each of said tables to impart a twist to the fibres being drawn from their respective bobbins whereby the fibres drawn from one of said tables are twisted to form the core of said strand, and the fibres drawn from said other tables are twisted in successive concentric layers upon said core, and means for individually controlling the relative revolutions of the respective tables with respect to one another for controlling the pitch at which the fibres drawn from the bobbins of the respective tables are twisted per unit length of the rope strand formed thereby so that the twist of the respective concentrically disposed fibre layers from the core to the outermost layer of said strand is progressively decreased so that in the finished strand the respective fibres of the core and the succeeding concentrically disposed layers are substantially equal in length for insuring that each of the strand fibres are unifonnly stressed under given load conditions.

2. The invention as defined in claim 1, wherein said table rotating means rotate each of said tables in the same direction.

3. The invention as defined in claim 1, wherein said table rotating means rotates one of said tables in one direction and another table in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 276,316 Wis-well Apr. 24, 1883 405,744 Root June 25, 1889 1,159,286 Smith et al. Nov. 2, 1915 1,210,001 Randall Dec. 26, 1916 1,992,707 Lloyd Feb. 26, 1935 2,098,922 McKnight Nov. 9, 1937 2,111,630 Johnson et a1 Mar. 22, 1938 2,149,312 Roche Mar. 7, 1939 2,190,854 Whitlock Feb. 20, 1940 2,281,036 I-Ietzel Apr. 28, 1942 2,714,414 Ganahl et a1 Aug. 2, 1955

Claims

1. A MACHINE FOR MAKING ROPE STRAND FROM A PLURALITY OF EITHE NATURAL AND/OR SYNTHETIC FIBRES, COMPRISING A PLURALITY OF TABLES, HOLLOW SHAFTING MEANS CONNECTING SAID TABLES IN CO-AXIALLY SPACED RELATIONSHIP, EACH OF SAID TABLES BEING ROTATABLY JOURNALED WITH SHAFTING MEANS, A PLURALITY OF BOBBINS HAVING FIBRE WINDINGS THEREON MOUNTED ON EACH OF SAID TABLES, THE BOBBINS MOUNTED ON EACH OF SAID TABLES BEING RADIALLY SPACED ABOUT SAID HOLLOW SHAFTING MEANS, MEANS FOR DRAWING THE FIBRES FROM THE RESPECTIVE BOBBINS OF EACH TABLE THROUGH THE HOLLOW SHAFTING MEANS, MEANS FOR ROTATING EACH OF SAID TABLES TO IMPART A TWIST TO THE FIBRES BEING DRAWN FROM THEIR RESPECTIVE BOBBINS WHEREBY THE FIBRES DRAWN FROM ONE OF SAID TABLES ARE TWISTED TO FORM THE CORE OF SAID STRAND, AND THE FIBRES DRAWN FROM SAID OTHER TABLES ARE TWISTED