US2865573A - Coil winder - Google Patents

Description

Dec. 23, 1958 s. v. TARARA El'AL 2,

con. WINDEZR Filed Oct. 6, 1954 4 Sheets-Sheet 1 FIG].

INVENTORS 30-/..- STEPH 1/. TA RA PAUL BER ATTORNEYS Dec. 23, 1958 's. v. TARARA EI'AL COIL WINDER 4 Sheets-Sheet 2 Filed Oct. 6, 1954 INVENTOR STEPHEN V. TARARA PAUL E ORE/P6 BY I Y M ,\9d4% MW ATTORNEYS D 5 v s. v. TARARA EIAL 2,865,573

' con. WINDER Filed Oct. 6, 1954 4 Sheets-Sheet 4 INVENTORS Q I STEPHEN v. TARA RA L PAUL 5 came ATTORNEYS 2,865,573 COIL WLNDER Stephen V. Tarara and'Paul E. Oberg, Minneapolis, Minn., assignors to'Sperry Rand Corporation, a corporation of Delaware Application October 6, 1954, -SerialNo.-460,586 IZ'Claims. C1. 24z' 4) This invention relates to coil winding machines, and more particularly to machines for winding strand material on toroidal cores.

Toroidal cores of ferro-magnetic material on which one or more windingsof an insulated conductor are wound in turns passing through the central aperture have innumerable applications in the electrical arts, and a great many machines for applying such windings have been developed with varying degrees of success. Heretofore, each of these machines has used an annular bobbin which can be interlinked with the core and then a supply of wire is wound on the bobbin. Windings may then be applied to the core by rotating the bobbin. Of necessity the diameter of the bobbin must be much greater than the crosssectional circumferenceof the core so that the portion of wire extending from the bobbin to the core varies cyclically, and just before the feed-out place of the bobbin reaches its most distant point from the core, there tends to be a sudden withdrawal of wire from the bobbin with a resultant danger of breakage. Considerable effort has been directed to the problem of easing sudden tensions, using such techniques as mounting the core in a manner allowing it to move to a limited extent to relieve tension on the wire, passing the wire between a stationary plate and a spring-mounted pad to maintain a continual and more constant tension thereon, and by mounting feedout devices on the bobbin. The latter operate in various ways and comprise the greater portion of improvements in toroidal coil winding machines. However, in each case they tend to increase the cross sectional area of equipment which must pass through the core and so they cannot be applied to the winding of very small toroidal cores.

The use of miniature cores has greatly increased in the electronic data handling art because of the power saving, the consequently lessened heat dissipation, and the saving in space and weight. Accordingly, a smaller core can be driven by a M. M. P. which can be created by a winding with a correspondingly smaller number of ampere-turns. In addition, a smaller core allows a greater number of turns to be applied from a given length of wire, thereby making the problem of storing the wire tobe applied to the core less acute.

Accordingly, it is an object of this invention to provide a coil winding machine wherein the mechanism which must pass through the core guides but does not store the wire so that the cross sectional area thereof is considerably reduced from that employedin other core winders.

Another object of the invention is the provision of a novel procedure for winding cores of far smaller inside diameter than-those which could previously be wound automatically.

It is a further object of this invention to provide positioning means for the unwound wire which apply a small,

steady tension thereto so that each turn is firmly laid' against the core or against previously formed turns and is held tightly in place during the formation of subsequent turns.

It is yet another object to provide means for readily ad'- 2,865,579; Patented Dec. 23, 1958 i 2 ju's'ting' tlie tension applied by the positioning means where; by windings ofuniform-qualitycan be achieved with wires of various strength and flexibility. I A further object is to provide a toroidal coil winder which substantially eliminates sudden tensions on the wire so' that windings can 'beproduced with wire of finer sire than could heretofore be used.

Another object of'this invention is to provide means for laying each turn substantially'parallel to the othe r'turns onthe core,- and when desired, to lay each turn immediat'ely alongside the previous turn but without over-' lapping the saniei A better understanding of the invention will be afforded by the following detaileddescription whenconsidered in connection with the accompanying drawings in which:

Figure l is a top plan view of a toroidal coil winding machine embodying the principles of the instant invention;

Figure Zisa perspective-view of the machine, p'artlyi cut-away to show the shuttle driving means.

Figure? is a cross-sectional view taken along line 33 of Figure 1 a Figure4 is a cross-sectional view taken along line 44 of Figure 3.

Figure 5-is a cross-sectional view of Fi ure 1. I I

Figure 6 is a fragmentary cross-sectional view taken along 'line 6 6 of Figure 1, showing the operation of the plunger whereby the wire-carrying capacity of the machine maybe substantially increased.

Figures 7-9 are diagrammatic illustrations showing in sequence the manner in which a turn of wire is formed on a toroidal core with the plunger in operation.

Figure 10 is-a "schemati'cview showing one embodiment of meansforautomatically controlling'the number of. turns.

Figure 11 is a top plan view of a modified form of driv ing'rriechanism for the shuttle, and

Figure 12 is a cross-sectional view taken along line 12 -12 of Figure 10.

Referring now more particularly to the drawings, there taken along line 55 is shown inFigures 1-l0 a coil winding machine including a needle-like split ring shuttle 20, having its extremities linkedannularly to form a separable joint 22. Sup-' porting the shuttle for rotation about its axis, is a plurality of drive rollers 24 having flanges 26 which are preferably formed of a resilient material, such as rubber or the like. Rotation 'is imparted to drive rollers 24 by means of any suitable power source such as electric motor 27 (see Figure 10), preferably from beneath a chassis top plat'e'28 in which roller shafts 30 are journaled. A toroidal core 32 tobe wound with strand material, such as wire or the like, is held by a core holder 34 in a position so that it may be interlinked withthe annular shuttle 20. The core holder 34 is in turn held by a sup mounted'on top plate 28. A flexible belt 54 riding in =a= Vj-groove'formed in the frame or brlstle-carrying'ring of circular brush 42 imparts angular rotation thereto. The-belt 54'is driven from drive wheel 56, against which it is tightly held by means of a pair of tensioning rollers 58, the bearings of which may be adjustably secured to support member 52 by any suitable means such-as bolts 60. Drive wheel- 56 is preferably geared to the-same motor or power source utilized to drive rollers 24= so 3 i that circular brush 42 is caused to rotate with substantially the same angular velocity as shuttle 20.

Rigidly mounted on the laterally extending portion 50 by a member extending through hollow shaft 44 are three straight brushes 6 2, 64 and-66. These brushes are pref erably arranged radially within the circle formed by circular brush42 and are disposed at angles in the order of 120 from each other, with brush 62 pointing toward toroidal core 32' as shown in Figure .1. A fourth straight brush 68 may be fastened to the outer" tip of brush 62 and extends outwardly therefrom so that over its length it isas near to the adjacent portion of circular brush 42 as may be practical. Both the circular brush 42 and stationary brushes 62, 64, 66, 68 are mounted so that their bristles just touch top plate 28 except in an area 70 underlying the core 32, which is preferably machined away to'provide a clearance in the order of one-eighth of an inch between circular brush 42 and top plate 28 for a purpose hereinafter to be described. The brushes may be of identical construction except that circular brush 42 is preferably about 3 inches in height whereas the straight brushes may'have substantially shorter bristles. In addition, brushes 62, 68 preferably have two rows of bristles to provide relatively greater friction to the wire passing under them, whereas stationary brushes 64 and 66 and rotating brush 42 preferably have a single row of bristles. A number of suitable bristle materials may be used, with nylon being preferred where fine wire is to be wound.

' After toroidal core 32 is mounted in core holder 34 and interlinked by shuttle 20, one end of a piece of wire 69 having a length equal to about one and one-quarter times the circumference of circular brush 42 is tied to shuttle 20 atthe slot formed by separable joint 22 (see Figure 3). The wire 69 is then laid around the circumference of brush 42, and the other end is tied at the core 32. The power source may then be switched on to rotate both the brush 42 and shuttle 20 and cause the wire 69 to be wound on the core 32.

Referring now more particularly to Figure 2, wherein the machine is cut away in part to show certain of the parts more clearly, it will be seen that rotation is imparted to drive rollers 24 through sheaves 72 on shafts 30 by means of a belt 74. Belt 74 and drive wheel 56- are both driven from the same power source (not shown) in such a manner that brush 42 and shuttle 20 rotate at approximately the same angular velocity. However, the angular velocity of brush 42 may be somewhat less but must not exceed that of the shuttle 20, for this would cause a loop of wire to form or begin to form between t 76 may be faced with non-resilient material to provide greater damping of any shuttle vibration in the vicinity of the core.

As the shuttle revolves, it draws the wire 69 into an ever smaller loop and pulls the end of the wire through the core 32 to lay a new loop around the outside of circular brush 42. As each loop is drawn toward the core 32, a moderate friction is applied to the wire by the bristles of both revolving brush 42 and stationary brushes 62, '64, 66, 6850 that a loop is maintained which is as freefrom-points of inflection as possible. Thebrushes also coac t fof-placea gentle tension on the wire 69 to form tight turns and hold previously formed turns tightly on the core, to keep the portion of the unwound wire which has not formed a loop from becoming tangled with that portion which has, and to hold the loop flat against the top plate 28 to guard against kinking.

The tension applied by circular brush 42 can be varied by means of a tensioning hoop 78 which rests lightly against the inner bristles of brush 42. It will be readily 4 appreciated with reference to Figures 2 and 3 that the relative stiffness of the bristles of brush 42 may be increased or decreased by lowering or raising the hoop by any suitable means such as screws 80 and slotted plates 82. Adjustable bristle tensioning is required for circular brush 42, because as each loop draws taut around the toroidal core, the succeeding loop is pulled past a great number of bristles on brush 42 almost simultaneously. This tends to cause the wire 69 to roll and hence gives rise to the possibility of kinking. Since the resistance of wire to torsional stresses varies considerably with changes in wire size, it is necessary to provide adjustable bristle stiffness so that siutable wire tensioning results. Accordingly, variation in the torsional force applied to the wire can be effected. Since only a small portion of wire is in contact with bristles of the stationary brushes at any instant, no means for adjusting the tension applied thereby is required. For the same reason, these brushes 62, 64, 66, 68 may have considerably shorter bristle length than circular brush 42, as has already been noted.

A subsidiary reason for providing adjustment in circular brush 42 lies in the fact that the wire filament is under maximum tension just as one loop draws taut and another begins to break through the brush 42. Any tendency toward wire breakage at this time could be alleviated by raising hoop 78 to lessen effective bristle stiffness. By the same token, heavier and consequently less flexible wire would call for greater bristle stiffness to insure that each loop is drawn taut before the succeeding loop is pulled toward the center.

As the loop becomes smaller, the wire is held against the top plate 28 by the brushes until it passes from beneath the same. During subsequent tightening of the loop it is necessary to keep it from flopping over and becoming entangled in the shuttle drivingmechanism. It is also necessary to bring the loop toward the core steadily and in suchamanner as to avoid kinking. To this end, a curved plate 84, having a wire guide 86 rigidly secured thereto, is bolted to chassis top plate 28 close to the shuttle 20 and may be provided with openings 88, 90 to provide clearance for the drive rollers 24. Wire guide 86, which may take the form of cylindrical rod, extends above and acros'sshuttle 20 in a generally curved shape to mark the extremity of an ideally-shaped loop of wire as it approaches core 32. Wire guide 86 also supports an upper brush guide 92 which coacts with lower brush guide 94 (Figure 3) to help lay each loop substantially parallel to previously formed turns. As the loop becomes small, it rides against the guide 86 and so is stabilized toprevent the formation of kinks. The action of wire guide 86 is particularly important where the wire size is very small and torsional stresses from the rolling action exerted by the brushes are concentrated into a shrinking loop.

The embodiment of this invention under consideration preferably incorporates means for counting the number of turns placed on a toroidal core and for stopping the winding operation upon reaching a predetermined count. A number of well known methods for counting each turn may be utilized with one such example being shown schematically in Figure 10. Since the circular brush 42 is rotated at substantially the same rate as the shuttle 20, revolutions of the brush may be noted by means of a micro-switch or a contact set operating in connection with a cam 102 on its shaft 44. However, it will be understood that where it is desired to slow the speed of brush 42 relative to that of shuttle 26 so that the rotation of brush 42 would not accurately reflect the number of turns being laid onthe core, the count could be made from the shuttle 20 or from a number of revolutions in its driving mechanism. For certain accuracy, the passage of that portion of wire 69 extending between shuttle 20 and brush 42 past a certain point could be noted. In any case, each count decreases the setting of an electromechanical counter 96. one unit. The number of turns desired is originally set into counter 96 and the counter is operable to open a switch 164, to. shut off the motor 27 when the counter reaches zero, so that the predetermined number of turns will be mechanically laid on the core. However, it should be noted that the total number of turns will include those applied to the core in tying the wire thereto and, in laying the wire around the brush. so that the counter 96 should be set to the required number of turns less one for each time the wire 69 is passed through the core in the setup operation.

Reference is now made to Figure 3 in which certain details in construction are more clearly illustrated. Shown in section are drive belt 54 and circular brush 42, to which tensioning hoop 78 is fastened by means of one of four slotted plates 82 and screws 80. By lowering or raising hoop 78, the effective length of the bristles of brush 42 is decreased or increased and the tension applied thereby to the wire filament correspondingly rnade greater or lesser. Also shown is the cutting away of top plate 28 in the area 70 to eliminate sweeping action of'brush 42 in that area (as marked out in Figure 1).

As the loop of wire is drawn inclose to toroidal core 32, it passes between brush guides 92, 94which cooperate with wire guide 86 to lay a turn on the core which is substantially parallel to previously formed turns 120. Whether turns 120 are applied to form a bunch or level winding depends on whether support bar 36 and core holder 34 are being oscillated so as to rotate core 32 upon its axis and, if so, upon the rate of rotation;

As shown in Figures 3 and 4, core holder 34 preferably comprises a cylindrical barrel 122 having projectingfingers 124, 126 which are connected at an intermediate point by a spreading bar 123. Barrel 122houses a helical spring 1313 which is retained by a threadedring 132'to exert pressure against a cylindrical projection 134 on a plunger 136. Referring now to Figure 4, a pair of leaf springs 138, 141) having inwardly turned outerends, and inner ends which are riveted to plunger 136, are shaped so that they are spread by bar 128 whenv plunger 136 is forced forward. Hence, toroidal core 321s lightly but firmly gripped between leaf springs 138, 141} and fin: gers- 124, 126 and may be removed by simply pressing plunger 136. I

Figure 4 also illustrates a preferred construction for the shuttle 2t and the manner in which'its separable joint may be formed. A single piece of hollow wire stock 142 is cut to a length just less than the desired circumference of the shuttle 20. A piece of piano wire 144 of a size suitable to provide a sliding fit within the cavity of the hollow wire stock is cut to exactly the desired shuttle length and then inserted in the hollow wire piece 142 so that one end projects therefrom a short distance, e. g., one-half inch. Then when the two ends of the assembly re joined in a ring, the hollow wire piece 142 will not quite close, leaving a small gap 146 to which the wire 69 may. be conveniently attached. The endsof the hollow wire piece 142 may be honed lightly to' hold abrasion between the wire and shuttle 20 to a minimum. It will be appreciated that with the shuttle having' a length such that it will just fit inside the drive rollers 24, the rollers will hold the separable joint 22 securely closed.

Referring now to Figure 5, there is shown a preferred form for drive rollers 24 which permits the shuttle 20 to be both positioned and joined in a single movement and incidentally holds stresses on the shuttle in the joining operation to a minimum. The shaft 30 of each drive roller 24 has a projecting central portion 160, the top of which fits fiush with resilient flanges 26. Flanges 26 are preferably rubber but may be formed of any semi-rigid material which would create substantial friction with the shuttle 20. The side 1 62 of central portion 160 is tapered to form an unbroken surface with the lower of flanges 26 and is curved to within approximately ten degrees of the vertical at the level of chassis top plate 28; Drive roller shaft 30 is so journaled in top plate 28 that-the central portion rides ina countera bore 164 thereof. It will be appreciated that if the shuttle 2.0 is laid on top plate 28 inside driverollers 24 and forced radially outward in order to join its ends, the shuttle will freely ride up tapered portions 160 and be lightly wedged against the flanges 26 of the drive rollers 24.

The coil winding machine as it has thus far been described is capable of winding on a core a length of wire equal. to about one and one-quarter times the circumference of the circular brush 42, less the distance from the core 32 to the furthermost point of the'shuttle 20' or the diameter thereof. While this capacity is normally adequate for the uses being made of and envisioned for this machine as will be demonstrated below, means will now be described whereby the length of wire available for winding may be greatly increased. A plunger 1-70 is mounted between the shuttle 20 and circular brush 42 a short distance in the clockwise direction from toroidal core 32, as shown in Figure 2 and by' a dotted line in Figure 1. The plunger is preferably actuated by a solenoid 178 and is mounted. beneath top plate 28 so as to either protrude therefrom or be retracted therebeneath as the solenoid is energizedlor de-energized. As shownin Figure 6, the plunger 170 is journaled ina plate 172 which is mounted between the top plate 28 and a. bottom plate 1740f the coil winder chassis. Plunger 170 is connected to bottom plate 174 through a spring 176 to be normally retracted belowthe surface of top plate 28. However, when solenoid 178 is energized, its plunger is retracted, and through the action of a lever arm 180, pivoted to plate 172 on a pin182, forces plunger 170 upward to the position. shown in. Figure 6. The plunger 170 is, in general, of cylindrical shape but iscut back at the top on'the side'nearestthe shuttle 20 and has a small cylindrical portionat its tip 184'. As the shuttle 21) draws wire 69 through toroidal core 32, it lays the wire against plunger 170 Ma point level with the shuttle and core. Then as the wire 69 is drawn along plunger 170, it rides up the tapered portion 186' until it is stabilized at plunger tip 184. The plunger 170 thus guides the wire to ride on circular brush 42 at a level substantially higher than the level 188*at which it would normally ride, thereby keeping the loop of wire being formed from becoming entangledwith the previously formed loop which will have been drawn down to approximately the level 188through the tension transmitted by.

the brushes through the wire from the toroidal core 32. When the plunger 171) is retracted, the wire 69 easily slips off the cylindrical tip 184 to ride against brush 42. Movement of plunger 170 is controlled through a' switch 19-1 which may be operated from the drive mechanism in synchronism with the movement of shuttle 211 by any'suitable means, such as a cam 1% on shaft 44.

The manner in which plunger 170 operates to increase the amount of wire which may be wound on a core is shown in Figures 7-9 which illustrate in sequence the forming of a turn 'on core 32. It should be noted that, in practice, it has been found to be impracticalto attempt to wind a wire of a length greater than about one and one-quarter wraps around brush 42 when the plunger 17%) is not being used. With plunger 17am operation, this length can be increased to at least one and seven-eighths wraps, the amount shown in Figure 7. Considerably longer pieces of wire can beused, but some danger of tangling is then encountered. Referringnow to Figure 7, the wire 69 is tied at one end to core 32 and then wrapped around brush 42, through the core, around plunger 170 which is initially set to protrude through top plate 28, and then tied to shuttle 20 at its separable joint 22 to form a loop 210 and a partial loop 212. As shuttle 21 is rotated in the clockwise direction, loop 210 is drawn inward through brush 42, and loop 212 isv completed as joint 22 passes through the core. When separable joint 22 reaches the position shown in Figure 8, plunger 170 ismomentarily retracted as explained above in connection with Figure 6, and loop 212 is drawn against brush 42. As shuttle 20 continues to move clockwise, loop 210 becomes even smaller as shown in Figure 9 and a new loop 214 is laid on plunger 170 and around the brush 42. By the time separable joint 22 completes a full revolution, loop 210 will have been drawn tightly around core 32, and loop 212 will begin to be drawn in toward the core. After enough wire has been used to reduce its length to somewhat less than one and one-quarter wraps around the brush, plunger 170 is rendered inoperative by the operator actuating switch 194 in the solenoid circuit. It is to be understood, however, that suitable means could be provided to render plunger 170 inoperative in response to the counter 96 reaching a predetermined setting.

It will also be appreciated that the machine could be provided with two or more plungers to further increase the winding capacity; The second plunger holding the wire at a slightly higher, level than that maintained by the plunger nearest the brush 42 while being synchronized with the shuttle 20 to drop its loop to'the first plunger shortly after the first plunger released its loop to the brush and was returned to position.

It has been found, however, that the wire-holding capacity of the present construction is entirely adequate for most purposes. To an average size core, 'inch in height with inside and outside diameters of and 71 inch, respectively, about 80 turns of No. 42 wire can be applied in a bunch winding without using the plunger on a machine having a circular brush about inches in diameter. When the plunger is used, the number of turns can be increased to at least 130. Much smaller cores can be wound using finer wire, the size of the core being limited only by the shuttle diameter plus clearance for the windings. Hollow wire stock having anoutside diameter of .018 inches is regularly used for the shuttle; a finer size could be used but would accordingly require more delicate handling and would have a shorter life. By rounding the corners of the toroids, the wire lies fiat against the core, keeping wire lengths and the clearance required for the windings at a minimum. 7

Reference is now made to Figures 11 and 12 wherein a modified form of the shuttle driving mechanism is shown. The shuttle 20, which is constructed in the same manner as previously described, is driven in a circular path by an endless flexible belt 220. As shown in crosssection in Figure 12, shuttle rides in a groove 222 of belt 220, which belt is in turn frictionally driven at a rectangular groove 225 by a geared ring 224 and pinion 226. Pinion 226 is geared to the power source so as to drive shuttle 20 with at least the angular velocity imparted to the circular brush. Ring 224 is rotatably mounted by means of its annular projection 228 which rides in a plurality of bearing members 230 positioned on chassis top plate 28. Belt 220 rides along ring 224 in the clockwise direction through approximately 310 of arc and is doubled back around a plurality of idler pulleys 232 as indicated by arrows 234 (Figure 11). Hence, shuttle 20 is not supported by the flexible belt 220 in the vicinity of toroidal core 32, but instead is guided by a pair of idler rollers 236. In order to provide maximum support for shuttle 20 in the vicinity of core 32, the shuttle is made slightly larger than the circle formed by groove 222 of belt 220, and rollers ,236 and core holder 34 are positione'd accordingly. The chassis top plate 28 is provided with a generally circular table 238, the top surface of which serves the same function as the portion of top plate 28 of Figure 1 lying inside shuttle 20. Hence, the top eighth of an inch of table 238 is cut away in the area 240, like area of Figure l, to minimize the sweeping action of circular brush 42. V p

It should be pointed out that adoption of the shuttle driving mechanism of Figures 11 and 12 would require the redesign of the plunger 170 for increasing wire capacity. To this end, plunger 170 could be suspended from outside and above flexible belt 220 and idler pulleys 232. In this case, the operation of plunger would of necessity be such as to lay the wire against the circular brush 42 at a level higher than that at which the wire would be laid if the plunger were inoperative. It is felt that such changes could be effected by anyone skilled in the art. Except as noted, the coil winding machine would be substantially identical to that illustrated in Figures 1-10 and operates in the same manner.

Operation To operate the species of the machine shown in Figures 1-10, a toroidal core 32 is clamped in place in core holder 34, and the shuttle 20 is passed through the core and laid on chassis top plate 28 between the circular brush 42 and the drive rollers 24. The ends of shuttle 20 are then joined, which operation causes the shuttle to ride up the tapered sides of drive rollers 24 to nest in the resilient flanges 26 thereof. Core holder 34 may then be adjusted in its mount 36, if necessary, to allow the shuttle 20 to freely pass through the center of the core 32. If the length of wire 69 to be wound on the core is greater than one and one-quarter times the circumferene of circular brush 42, solenoid 178 is energized to project plunger 170 through chassis top plate 28. The wire 69 is next tied to core 32, laid around circular brush 42, passed through the core and round plunger 170, and tied to the separable joint 22 of shuttle 20, which is first moved to a position allowing the wire 69 to be laid along brush 42 without slack. The counter 96 is then set to indicate the number of turns required in the winding less one turn for each time the wire is manually passed through the core before the power is switched in. If a layer or level Wind is desired, the core-oscillating mechanism is adjusted accordingly or otherwise set to zero for a bunch winding. Power is applied to increase gradually the rotational speed of the shuttle 20 and circular brush 42. After the length of unwound wire 69 has decreased to less than one and one-quarter wraps around brush 42, the solenoid'178 is cut out to permanently retract plunger 170. When counter 96 indicates zero, the machine is quickly brought to a stop automatically, the wire 69 cut to provide a lead from the winding of the desired length, and the core either removed or set to a different position for the application of another windmg.

Although the invention has been described in connection with the winding of wire on toroidal cores, it ohviously could be applied to the winding of any kind of strand material and to the application of strand material to objects having other than a toroidal shape.

The foregoing detailed descriptions have been made only for purposes of illustration, and obviously many modifications and variations could be made without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. A machine for winding strand material around a -closed core comprising a shuttle rotatable through a core arranged to have one end of a length of strand material greater than the diameter of the shuttle secured thereto, means on said shuttle to which the other end of the length of strand material is fixedly attached to form a fixed point of departure of the length of strand material from said shuttle during the rotation of the latter, and means separate from said shuttle around a portion of which loops are formed during the rotation of said shuttle in the entire portion of the length of strand ma terial extending from said fixed point of departure to said core and for maintaining said loops in untangled condition as the latter are tightened around said core by rotation of said shuttle. I

2. A machine as defined in claim 1 wherein said shuttle is provided with means for rotating the same, said shuttlerotating means comprising a ring, said shuttle being concentric therewith, a plurality of rollers mounted for rotation about parallel axes spaced circumferentially about the axis of said ring outwardly of the periphery thereof, an endless belt trained around said rollers and substantially around the exterior periphery of said ring leaving a gap adjacent the core, the shuttle engaging the interior periphery of the portion of said belt which engages said ring, and means for driving said ring.

3. A machine as defined in claim 1 wherein said shuttle is provided with means for rotating the same, said shuttle rotating means comprising a plurality of drive rollers rotatable about parallel axes spaced circumferentially about the axis of the shuttle outwardly thereof, each of said rollers having an angular groove formed therein for receiving said shuttle and an annular outwardly flared lower portion forming an unbroken surface extending from said groove, and means for driving said rollers.

4. A machine as defined in claim 1 wherein said loo-pforming means comprises brush means surrounded by said shuttle and having bristles, and means providing a surface in engagement with the free ends of said bristles for supporting the length of strand material in engagement with the free ends of said bristles.

5. A machine as defined in claim 4, wherein said surface providing means includes a depressed surface portion adjacent the core disposed out of engagement with said bristles.

6. A machine as defined in claim 1, wherein said lastmentioned means includes guide means adjacent the core for handling successive loops just prior to their being tightened on the core, said guide means including a rod adjacent the core extending above and across said shuttle in a generally curved shape conforming to the extremity of an ideally shaped loop.

7. A machine as defined in claim 6 wherein said guide means also includes a pair of opposed brushes having bristles arranged so that successive loops are engaged between the free ends thereof.

8. A toroidal coil winding machine comprising a shuttle rotatable about its axis through a core, means for rotating said shuttle to wind a length of strand material extending therefrom around the core and means operable to yie1dingly engage the length of strand material extending between said shuttle and the core for maintaining the same in an untangled condition as successive loops thereof are tightened around the core during rotation of said shuttle, said last-mentioned means including a rotatable circular brush surrounded by said shuttle and having its axis of rotation coincident with the axis of rotation of said shuttle, and means for rotating said brush about its axis at substantially the same speed as said shuttle.

9. A machine as defined in claim 8, including stationary brushes mounted within said circular brushes.

10. A toroidal coil winding machine comprising a rotatably shuttle for rigidly receiving one end of a length of strand material considerably greater than the diameter of said shuttle, means for rotating said shuttle about its axis through the core to wind the length around the core, means separate from said shuttle around a portion of which successive loops are formed during rotation of said shuttle in the entire portion of the length of strand material extending from said one end to the core and for maintaining said loops in an untangled condition as the latter are tightened around the core by rotation of said shuttle, said loop-forming means including a circular brush surrounded by said shuttle and having bristles extending generally transverse with respect to the plane of the shuttle, and guide means including a movable plunger between said shuttle and said brush for directing the length onto said bristles during rotation of said shuttle so as to prevent entanglement of successive loops thereon.

11. In a machine for winding a length of strand material around a closed core, a shuttle rotatable through the core arranged to have one end of a length of strand material greater than the diameter of the shuttle secured thereto, said shuttle comprising a split ring of hollow Wire construction having spaced-apart ends and a Wire of slightly greater length than the length of the split ring mounted within said split ring, one end of said wire terminating within said split ring adjacent one end thereof and the other end of said wire extending outwardly from the other end of said split ring, the outwardly extending end of said wire being insertable in said one end of said split ring so as to engage said one end of said wire, the portion of said wire extending between the spaced-apart ends of said split ring being arranged to have the opposite end of the length of strand material secured thereto, the spaced-apart ends of said split ring maintainng the end of the length of strand material secured to said wire portion against movement in either direction along the circumferential extent of said shuttle during the rotation of the latter.

12. A method of winding strand material around closed cores which comprises securing to a shuttle one end of a length of strand material greater than the diameetr of the shuttle forming a fixed point of departure of the length of strand material inwardly toward the axis of the shuttle, securing the opposite end of the length of strand material to the core to be wound, rotating the shuttle about its axis through the core, and restraining movement of the entire portion of the length of strand material extending from said fixed point of departure to the core so as to maintain it in an untangled condition during the rotation of the shuttle.

References Cited in the file of this patent UNITED STATES PATENTS 1,305,910 Liddell June 3, 1919 1,679,804 Bisel et al Aug. 7, 1928 1,851,243 Egli Mar. 29, 1932 2,331,674 FOX Oct. 12, 1943 2,444,126 Wirth June 29, 1948 2,672,297 Harder Mar. 16, 1954 2,699,902 Wirth Ian. 18, 1955 FOREIGN PATENTS 639,177 Great Britain June 21, 1950

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