US2234996A - Cable-making machine - Google Patents

Description

March 18, 1941.

A. u. WELCH, JR., E'TAL CABLE-HAKING HACHINE Filed Aug. 31, 1939 :s sheets-Shen 1 bg 5V The `Attcr`neg- A. U. WELCH, JR., ETAL 2,234,996

cnam-mama nomas k'Film1 Aug. 51. 1939 a sheets-snag;

Inverwtors: Alanso'n Ll. Welch,Jr`.,

Curtiss M. Cederstrcm,

Maj-ch 18, 1941 A. u. WELCH, JRu., .ETAL 2,234,996

CABLE-AKING IACHINE Filed Aug. 31, 1939 3 Shasta-Sheet 3 n Jm 9 e SIS n Ver u O tudom nnf SOM. nl V S hn h AP Q b i Patented Mar. 13, i941 UNITED STATES PATENT OFFICE CABLE -MAKING MACHINE Alanson U. Welch, Jr.,

and Curtiss M. Cederstrom,

Application August 3l,

8 Claims.

Our invention relates to cable-making machines. The general object oi the invention is to provide an improved machine for making substantially rectangular, stranded cable from insulated, rectangular strands or wires, this typeof cable being particularly well suited for use in forming electrical apparatus windings.

The invention will be better understood from the following description taken in connection with the accompanying drawings in which Figs. l` and 2 show the structure oi a piece of cable of relatively few strands which may be made by a machine constructed in accordance with the invention, Fig. 1 showing the cable in perspective and Fig. 2 showing diagrammatically the relationship between successive cross-sections 2a to 2u inclusive of the cable; Fig. 3 is a side View of a machine constructed in accordance with the invention for making cable of the type shown in 2 Figs. l and 2; Fig. 4 is a sectional view on the line 4-4 of Fig. 3; Fig. 5 is a sectional View on the line 5--5 of Fig. 4; Fig. 6 is a sectional view on the line 6--6 of Fig. 3; Fig. 7 is a sectional view on the line 'I-l of Fig. 3; Fig. 8 is a sectional view on the line 8 8 of Fig. 7; Fig. 9 is a sectional view of a modied form of cable which may be made by a machine constructed in accordance with the invention; Fig. 10 is a sectional View of a transposing mechanism for transposing the strands of the form-of cable shown in Fig. 9; Fig. l1 is a sectional view of another modified form of cable which maybe made by a machine constructed in accordance with the invention; and Fig. l2 is a sectional view of a transposing mechanism for transposing the strands of the form oi cable shown in Fig. 11.

Similar reference characters indicate like parts oi all of the figures in the drawings.

The cable I0 shown in Fig. 1 of the drawings 40 is formed of five insulated strands 1|, l2, ist, u and I5 arranged in substantially parallel planes and in such manner as to constitute a substantially rectangular conductor with a constant n width of two strands and a constant thickness of three strands. The strands are transposed without being twisted. The transposition of the strands without twisting is accomplished by progressive bending and reverse bending of the strands alternately along their width and along their thickness. When a strand is bent edgewise, the orientation of its plane is not affected at all cf course. When bent atwise, its plane is slightly changed in a mathematical sense but, as will be obvious from the drawings, such bending is slight and occurs in only a small portion 1939, serial No. 292,905 (Ci. 57-459) of the strand so that the plane of the strand quickly returns to its earlier orientation by the reverse bending of the strand. In other Words, the orientation of the plane of each strand is generally constant but undulates slightly when 5 considered at certain short intervals.

The arrangement of the strands in the cable ymay be clearly understood by reference to Fig. 2 which shows a series of successive cross-sections 2a to 2u inclusive of the cable shown in Fig. 10 l. Starting with the arrangement of the strands shown in section 2a, the strands I4 and I5 are bent progressively upward until the arrangement shown in section 2b is reached. The arrow I6 indicates the direction of the force which brought about the change from the preceding section 2a. The strand I3 is now bent edgewise by a force acting in the direction indicated by the arrow Il until the arrangement shown in section 2c is reached. The strands II and I2 are now bent 20 downwardly together until the arrangement shown in section 2d is reached, the direction of the bending force being indicated by the arrow I8. The strand I5 is next bent edgewise until the arrangement shown in section 2e is reached, 25 the direction of the bending force being indicated by the arrow I9. The successive bending of the strands continues indenitely through the various stages indicated in successive sections and throughout manycycles for the entire length of the cable. It will be seen that the arrangement of the strands in the section 2u is identical with that in section 2a and that between these two sections every strand in succession occupies every position inthe cable and for an equal distance along the cable. In other words, between A the sections 2a and 2u the strands have undergone one complete cycle of transposition. This equalizes the iiux linkages of all of the strands in this length of the cable and balances out differences in strand voltages which would otherwise tend to set up circulating currents among the strands. The best results are obtained when the alternating magnetic eld in which the cable may be located is substantially constant for at least a distance equal to the length of the cable corresponding to one complete cycle of transposition, but great benefit is secured even when this condition is not perfectly fullled. In general, the magnetic field does not have to be uni- 50 form in the plane of the cross section of the cable and the eld distribution may be different along different cycles of transposition Without 11npairing the eiect of the transpositions. Ii the cable is used as a straight conductor, the length of the cable along which a cycle of transposition is completed is relatively unimportant, provided that that length does not greatly exceed the length of the table to be used. But in the use of the cable in electrical apparatus windings, differential voltages in the strands at any point of the cable are produced not only by the currents in that part of the cable but also by lthose in other parts of the winding and therefore it is desirable that these progressive transpositions be completed in as short lengths of the cable as practicable without resorting to such sharp bending of the strands as would harm any insulation on the individual strands.

It will be obvious from a consideration of Fig. 2 that the width of the cable is constant and is everywhere exactly equal to the width of a row of two strands and that the thickness of the cable is also constant and everywhere exactly equal to the thickness of a column of three strands. The constancy of thickness is assured by the use of an odd number of strands in the cable. If an even number of strands were used, say six strands instead of ilve, the progressive transpositions of thelstrands would make them occupy successive positions like those illustrated in Fig. 11, which will be described later, b ut from which it is clear that the thickness of the cable would fluctuate at frequent intervals between the thickness of three strands and the thickness of four strands. This may be undesirable in an electrical apparatus winding if the strand thickness is an appreciable fraction of the thickness of the cable and therefore the cable with the odd number of strands and a. constant thickness may be preferred, but when the strand thickness is small or a non-constant thickness of the cable is not objectionable, a cable with an even number of strands may be used. If the individual strands are very thin so that the thickness of I a cable having an even number of strands is not far from constant, thethin strands tend to buckle when they are bent edgewise so that the preferable method of securing a constant thickness of the cable is the use of an odd number of strands. The absence of a single strandin the cable having an odd number of strands not only does not result in a smaller space factor but actually increases the space factor as compared with a cable having bulging portions resulting-from the use oi an even number of strands. While in neither case is the cross section of the cable a perfect and complete rectangle all along the cable, yet the cable having an odd number of strands, by virtue of its constant width and thickness and the smoothness of it'ssides, nts perfectly for all practical purposes into a rectangular slot of an armature or into a rectangular winding space of a transformer winding.

It will be seen that a cable such as is shown in Fig. l will have great rigidity in the direction of the width of the strands, the rigidity depending on their width and great exibility in the direction of the thickness of the strands, this flexibility depending on their thinness. As the planes of the strands are never twisted, the directions of rigidity and flexibility of the cable are unchanged all along the cable.

Cables such as have been described are particularly valuable for winding solenoidal coils in which the width of each strand is parallel to the axis of the solenoid so that in forming the coil the cable is bent in the direction in which it is mostexible and the strands are orientated with their widths parallel to the general direction of `the strands reduces the eddy currents between .the strands, it does not reduce eddy currents within the individual strands. Eddy currents Within the individual strands are reduced by orientating the strands so as to make their wider dimensions parallel to the iiux flowing through them. As the ilux in a solenoid is predominantly axial, the benefit of the parallelism of the strand width to the axis of the solenoid throughout the coil will be appreciated. As a result it will be seen why the present invention aims at keeping the planes of the strands untwisted and sub stantially parallel throughout the length of the cable and it will also be seen that considerable undulation of the planes of the strands arising from their flatwise bending is permissible as this does not tend to turn the width of the strand away from parallelism with the width of the cable and the axis of the solenoid.

A cable-making machine made in accordance with the invention for forming substantially rectangular, stranded cable is illustrated in Fig. 3 of the drawings. The cable and the method of forming it are disclosed and claimed in our ap plication Serial Number 292,904, iiled concurrently herewith, but the cable and method are shown and described here in order to make more clear the operation of the machine of our invention. The machine is shown as arranged for forming a cable of ve strands and includes ve reels 2Q, each reel holding a roll of rectangular, insulated wire 2| to be made into the desired cable. Fig. 6 shows these reels more clearly. The reels 20 are pivotally suspended from projecting arms of a support 22 which may be rotated about its axis by a motor 23 through a suitable reduction gear mechanism in a gear box 24. In this particular embodiment of the invention, the reels 2li are suspended with their axes arranged vertically and cach reel is rotatable about its own axis. 'Ihe reels 2B are suspended from horizontal axes parallel to the axis of rotation of the support 22 with the centers of gravity of the reels below their pivotal supports so that, as the support 22 is rotated and the rolls of wire 2i on the reels 2li are carried around with it, the axes of the reels 26 and rolls of wire 2i are maintained all and unchanging and to prevent their twisting as the strands of wire revolve in unison With the tube 21, the bushings 26 and the reels 2B. A sectional view oi the planetary gear mechanism 29 is shown in Fig. 7. This planetary gear mechanism includes a vertical plate 30 which forms part of the housing for the planetary gears. Five gears 3| distributed about the axis of the plate 3G are plvotally supported in openings in this plate, as indicated in the sectional view shown in Fig. 8. Five intermediate gears 32 distributed also about the axis of the plate 3B are arranged in mesh respectively with the five gears 3i and are also pivotally mounted in openings in the plate 30. A central gear 33 is also pivotally mounted in an opening in the plate 38 and is secured to a rod 34 which extends back along the. axis of the tube 21 and is secured to the fixed support 35 carrying the reel support 22 so that this rod 34 and the central gear 33 of the planetary gear mechanism are xed and cannot rotate. Each of the outer gears 3| is formed with an axial opening for one of the strands from the reels 20 to pass through. The openings in the gears 3| are similar in cross-section to that of the strands and just large enough to permit the strands to pass through without excessive friction while functioning at the same time to guide the strands and maintain their planes constantly parallel to each other and to a fixed plane. Each pivotally supported gear 3| is geared to the stationary central gear 33 by one of the rotatable intermediate gears 32. It will be seen that as the plate 39 is rotated by the tube 21 and in unison with the reels 20, the gears 3i and 32 will be carried around the stationary gear 33 in the same direction. If these gears 3| and 32 were not geared to the stationary gear 33, their motions around the stationary gear 33 would result in an equal rotation around their own axes. However, as they are geared to the stationary gear 33, the intermediate gears 32 are forced to rotate in the saine direction as that of the plate 38 so that these intermediate gears 32 will tend to rotate the outer gears 3| in a direction opposite to that ci the plate 39. If the stationary gear 33 and the outer gears 3| have the same number of teeth, it will be seen that the outer gears 3| are prevented -from any rotation about their own axes. The openings in the gears 3| thus maintain the planes of the strands passing through them constantly parallel to each other and to a xed plane as the strands are carried around the axis of the machine. As shown in the drawings, the planes of the strands are maintained always in horizontal positions.

Leaving the planetary gear mechanism in proper orientation, the strands to I5 inclusive are brought together into a transposlng mechanism 36 shown in the sectional views in Figs. 4 and 5. This transposing mechanism includes a stationary housing 31, a rotatable internal cam 38 and four floating fingers 39, 49, 4| and 42, the function of these fingers being to transpose the strands as they are brought together to form the cable. The positions and movements of the transposing fingers 39 to 42 inclusive are controlled by the internal cam 38, springs 43 and links 44, 45, 46 and 41 which are pivotally connected between the fingers as shown. The outer perimeter oi the internal cam 38 is circular and is provided with sprocket teeth 48 to permit it to be driven by a chain drive 49 from the shaft 59 which is driven by a chain 5| and the gear mechanism in the gear box 24. The inner cam surface of the cam 38 is formed so that one half of it, shown at the left in Fig. 4, is concentric with the axis of the cam, the next quadrant shown at the lower right gradually approaches the axis of the cam and the remaining quadrant is again concentric with the axis ofthe cam. A nxed plate 53 is secured by pins 54 to raised l portions 55 of the housing 31 and has a central rectangular opening corresponding to the dimensions of the cable. This plate 53 is positioned close beside the transposing ngers 39 to 42 inclusive and its rectangular central opening guides the cable and confines its strands within the contour of the cable as they are being transpcsed so that orientation and sequence of the strands are maintained. With the positions of the fin' gers 39 to 42 inclusive, as shown in Fig. 4, where the strands of the cable are arranged as shown in Fig. 2a, the ringer 40 is held in position against the strand I3 by the link 44 and the two springsl 43 connected to this link and also by the link connected between the fingers 40 and 4I. This finger 4D will remain in this position for another quarter rotation of the cam 38 which rotates in the direction of the arrow 52. The finger 39 has just been released by the cam 38 to permit this finger 39 to be pulled upwardly by its spring'y 43 and a notch at its lower end to engage the' strand Il when pulled back over that strand by the link 41. The finger 39 will remain in its new position for half a rotation of the cam 38. The finger 42 is now being pressed against the strand il by the cam 38 and will remain in this position for another quarter rotation of the cam. The ringer 4| is being held up to engage the strand I4 in its notch by the link 46 which is connected between the fingers 4I and 42. After a small further rotation of the cam 38 in the direction of the arrow 52, the cam will engage the lower end of the'nger 4I and begin to force this finger upwardly to bend the strands i4 and I5 so that the strand |4 will then reach the space previously occupied by the strand |5. The strands will then occupy the positions shown in Fig. 2b. The rising portion of the cam 38 will now have approached the linger 40 and during its next quarter rotation will push this nger to bend the strand I3 to the right, the strands then occupying the positions shown in Fig. 2c. In the next quarter rotation of the cam 38, the cam will push the finger 39 downwardly and this will bend the strands and I2 to bring the strands into the positions shown in Fig. 2d. Another quarter rotation of the cam 38 will finish one complete rotation thereof and will push the nger 42 to the left, bending the strand I5 to the left and leaving the strands in the positions shown in Fig. 2e. This sequence of operations will be repeated indefinitely, making cycle after cycle of transpositions of the strands along the cable. While the transposing mechanism is operating, the strands are pulled through it and through the diierential gear mechanism 29 from the reels 2U so that successive transpositions of the strands take place at successive intervals along the strands and the cable and the strands leave the transposing mechanism in the form of the cable shown in Fig. l. The sprocket teeth 48 along the outer edge of the cam member 38 are driven by the motor 23 through the sprocket chain 5|, the shaft 50 and the sprocket chain 49. The rotation of the reels 20 and their rolls of wire 2| and the rotation of the cam 38 of the transposing mechanism 36 are thus mechanically coupled. The proper ratio between the rates of rotation of the cam 38 and the revolving reel support 22 which this coupling must maintain is determined by the consideration that one complete rotation oi the cam 38 changes the position of the strands from that shown in Fig. 2a to that shown in Fig. 2d, a change-'representing a rotation of the positions of the strands by the distance between twoadjacent strands. As a complete cycle of transpositions oi the strands requires a complete rotation of the positions of the strands, in the present case five strands, the mechanical coupling between the cam 38 and the reel support 22 must be such as to cause rive revolutions of the cam 33 to one revolution of having a width of two strands this ratio will be the same as the number of the strands. After l leaving the transposing mechanism 36 the cable is passed through a conventional insulation covering machine 56 which wraps cotton, paper or other insulating strips around the cable. An extra supply of rolls of insulating tape or ribbon el may be provided on a tubular support 58 surrounding the cable so that when the rolls 59 are.

used up they may be replaced without cutting the cable. The insulated cable is now passed from the insulating mechanism 56 through a winch mechanism 6d which is driven by a motor di and a sprocket chain E2 to pull the cable through the preceding mechanisms and feed it onto a reel 63 which is driven by a motor 6d and a sprocket chain 65. The reeling machine may include a. conventional reciprocating guide 65 for guiding the cable onto the reel 53. The winch mechanism 6@ and the reeling mechanism for driving the reel 63 may be of any conventional types and none of the features of these mechanisms constitute part of tle present invention.

It will be seen that mechanical coupling is provided between the insulation wrapping mechanism 5e and the `winch mechanism di) through a shaft El which is driven by the same motor tit that drives the winch mechanism Eil. Such coupling is desirable to secure uniform application of insulation tothe cable.

In the parts of the machine so far described no mechanical coupling is provided between the transposing mechanism 36 and the winch mechanism 6U because the length of cable along which each complete cycle of transposition is effected need not be precisely the same for each cycle of transposition and therefore the ratio of the motions of the transposing mechanism 36 and the winch mechanism e@ need not be precisely maintained. It is obvious, however, that any suitable coupling may be provided between such mechanisms if so desired.

.Stranded cables are frequently made by adding layer after layer of strands to a central longitudinal core. A machine constructed in accordance with the invention may be used in the production of that type of cable. Fig. 9 shows sectional views sa, 9b, se and 9d taken at equal, short intervals along such a cored cable. The central rectangle in these sections is the core of the cable and is shown here as having the width or two strands and the thickness of three strands. The strands of the outer layer of this cored cable are arranged lengthwise of the core with their planes substantially parallel and they form a layer around the core to provide an enlarged substantially rectangular conductor. One strand is omitted from this outer stranded layer to make room for transpositions without overbuilding the width or thickness of the cable at recurrent intervals. The strands are transposed by rotating them around the core in a manner exactly similar to that already described in connection with the machine shown in Fig. 3. The same machine may be used except that the number of reels 2! should correspond to the number of strands. The transposlng mechanism is shown in Fig. 10 and is exactly like that shown in Fig. 4 except that the proportions are changed because of the greater width and thickness of the cable. Comparison of the sectional views of the cable shown in Fig. 9 will show that the positions of the strands have been rotated by the dimensions of 'the reel support 22. It will be evident that in .cables formed of an odd number of strands and one strand at each transposition point and that if this operation is carried on until the number of transpositions equals the number of strands, then the strands will have undergone one complete cycle of transposition. The cycles of transposition are repeated indefinitely for the entire length of the cable. Additional layers may be placed on the cable in the same way to build up still larger cables in the same manner. 'A central core of the cable may be formed of transposed strands, as shown in Fig. 10, but it may obviously be in the form of a single solid conductor if desired.

Successive sections of a stranded cable formed from an even number of conductors are shown in Fig. 11. It will be obvious that the width of this cable is constant but that the thickness undulates between that oi three conductors and that of four conductors. The same machine `which has been described and which has been shown in Fig. 3 may be used to transpose the strands of this cable except that the transposing mechanism is somewhat different as shown in Fig. 12. In this transposing mechanism the internal cam il is a double cam, both halves of the cam being similar. With the positions of the cam il and the ngers 7E, 13, lil and i5 as shown in Fig. 12, the cam has just pushed the fingers 73 and l5 inwardly to bend the upper and lower strands of the cable into the positions shown in the figure. The ngers 'l2 and lf3 have been released by the cam and pulled back from the cable by their springs i6. A quarter rotation of the cam li in the direction of thearrow 'il will iirst push the ngers 'i2 and lil to bend the left and right columns of strands in opposite directions until they are in the relative positions shown in Fig. 11b. Just at the completion of this motion of the cam, the fingers l'and l5 will be released and retracted by their springs l@ into positions ready to engage the upper and lower single strands as shown in the section of Fig. 11b. These upper and lower single strands will be held in this position by the fingers it and 'l5 during the succeeding revolution of the cam 'il while the cam is forcing the fingers l2 and l@ again towards the cable to bend the left and right columns of strands into the position shown in Fig. 11d. This sequence of operations is repeated indefinitely throughout the length of the cable.

In each of the forms of cable which have been described the transposing of the strands throughout many cycles produces a cable having a plurality of superposed rows of strands arranged in a plurality of columns, the transpositions causing the strands to change their positions progressively around the axis oi the cable but at the same time maintaining the same sequence and without twisting the individual strands.

The invention has been explained by describing and illustrating a machine and certain modiiications thereof for making particular forms of transposed, stranded cable, but it will be apparent that other changes may be made without departing from the spirit of the invention and the scope of the appended claims.

What we claim as new and desire to secure by Letters Patent of the United States, is:

l. A machine for making a stranded substantially rectangular cable from a plurality of rectangular strands, the machine including means for bringing strands of wire together and maintaining them in a rectangular grouping, means for moving said group of strands, a plurality of ananas sively without twisting into positions extending around the axis oi the group.

2. A machine for making a stranded substantially rectangular cable from a plurality of rectangular strands, the machine including ineans for bringing strands oi wire together and maintaining them in a rectangular grouping, means for moving said group of strands. a plurality of movable transposing fingers, and means including a cam for operating said fingers to bend the strands progressively without twisting into positions extending around the axis oi' the group.

3. A machine for making a stranded substantially rectangular cable from a plurality ci rectangular strands. said machine including a fixed guiding member having a rectangular opening for a rectangular assembly o! strands in' a plurality of rows and columns, a plurality of movable ilngers near said opening for engaging the assembly of strands at a plurality of points'. and a cam for operating said iingers to bend a row of strands and a column oi' strands alternately to cause the strands to extend around the axis of the group.

4. A machine for making a stranded substantially rectangular cable from a plurality of rectangular strands, said machine including a fixed guiding member having an opening for a rectangular assembly ot strands in a plurality of rows and columns, said opening being rectangular to maintain said assembly ot strands in a rectangular and untwisted group, four movable ngers near said opening and extending substantially radially therefrom, links pivotally connecting adjacent fingers, a resilient member i'or retracting each finger from an assembly of strands in the opening, and an internal cam surrounding said i'lngers for operating them to bend a row oi strands and a column of strands alter-` nately to cause the strands to extend around the axis of the group.

5. A machine i'or making a stranded substangear, and intermediate gears between said stationary gear and .said pivotally carried gears for maintaining the orientation ot said pivotally carried gears to prevent twisting of said strands during rotation ot said gear support.

6. A machine for making a stranded substantially reotangularoable from a plurality of rectangular strands, said machine including a rotatable supportfor a plurality of rolls of strands, winch means for unreeling said strands in unison, means for bringing said strands together into a rectangular group forming a stranded cable, and means including a cam and transposing fingers to bend said strands while maintaining them untwisted so as to cause them to extend around the axis of the group.

7. A machine for making a stranded substantially rectangular cable iroma plurality oi' rectangular strands, said machine including a rotatable reel support, a plurality of reels for holding rolls of strands, said reels being pivotally suspended from said support, a iixed guide member having an opening Ior'said strands, which means for withdrawing strands in unison from said reels and throughsaid opening, said opening being rectangular to maintainlthe assembly of said strands,Y and means includingarotatable gear support and a plurality `oi? planetary gears having openings for guiding said strands toward said fixed guiding'member, anda' common driving mechanism for said reel support and said strand guiding gearsto revolve said reels and gears inunison. n Y g Y `8.' AA machine for making ya stranded substantially rectangular cable' from a plurality of rectangular strands, said machiney including a rotatable supportior a' pluralityv oi rolls o! strands, a guiding member-having a. rectangular opening ior said strands, `winchmeans for withdrawing strands in unison from said support and through said opening, transposing means including acam and a plurality o'i ilngers for bending said strands in succession as they approach said opening, a rotatable support, and planetary rotatable guide members carried by said support for 'revolving said strands in unison with said reels to maintain unchanged the orientations of the planes oi the strands as they approach the .transposing reels.

ALANSON U. WELCH, Jn. CURTISS M. CEDERBTROM.

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