US2978193A - Winding machines - Google Patents

Description

April 4, 1961 Filed Aug. 29, 1955 R. J. KELLY WINDING MACHINES 5 5 7 w W i A 30 "-iv TIZT- 4 6 50004; d. KELL Y ATTORNEY 5 Sheets-Sheet 2 April 4, 1961 R. J. KELLY 2,978,193

WINDING MACHINES Filed Aug. 29, 1955 5 Sheets-Sheet 3 INVENTOR ATTORNEY April 4, 1961 'R. J. KELLY WINDING MACHINES 5 Sheets-Sheet 4 Filed Aug. 29, 1955 INVENTOR ffz/aoz P// (1 K5 LLY ATTORNEY April 4, 1961 R. J. KELLY 2,978,] 93

WINDING MACHINES Filed Aug. 29, 1955 5 Sheets-Sheet 5 INVENTOR ATTORNEY United States Patent WINDING MACHINES Rudolph J. Kelly, Smithtown, N.Y., assignor to Sperry Rand Corporation, Great Neck, N.Y., a corporation of Delaware Filed Aug. 29, 1955, Ser. No. 530,967

'8 Claims. (Cl. 2421.1)

This invention relates to improvements in winding machines and more particularly to apparatus for winding strand material such aswire on closed cores such as toroids, dynamoelectric machine stator cores and the like.

, In order to wind a continuous length of wire on a toroid or similarly closed core, it is necessary, in winding each successive turn, to pass the entire remaining body of wire through. the aperture in the core. This requirement has been met in prior art devices by storing the wire on a ring-like shuttle that is made to interlink with the core to be wound. One end of the wire is fastened to the core, and the shuttle is rotated to' carry the stored wire repeatedly through the aperture in the core, pulling the wire off the shuttle and winding one turn on the core during each revolution of the shuttle. The shuttle is hinged or split so that it can be inserted through the core before loading, and removed from the core after it is emptied. An early example of a machine using a ring type shuttle is shown in Pupin et al., Patent No. 697,660. A modern machine of similar type is shown in Wirth Patent No. 2,444,126.

Winding machines of the abovementioned type are subject inherently to two disadvantages: first, the amount of wire that can be wound without stopping the machine, reloading the shuttle, and splicing the wire is limited to the quantity that can be stored on the shuttle; second, the extent to which the core aperture can be filled with 'the'winding is limited by the cross sectional area of the shuttle ring.

One of the principal objects of the present invention is to provide Winding machines in which no shuttle is used, thereby avoiding the foregoing disadvantages.-

Another object is to provide an improvedtype of winding machine that is capable of filling an aperture substantially completely without finishing the winding by hand and without reloading the machine.

A furtherobject is to provide winding machines that are adaptable to winding coils in place on stators of dynamoelectric machines and similar devices.

Another object is to provide improved winding machines of the described type wherein the strand material to be wound is released turn by turn from a storage skein automtically, and under a predetermined tension, without manual intervention.

According to the present invention, the above objects are achieved by storing the wire in the form of an open skein supported at its ends on drums or pulleys which are outside the core to be wound. In the case of a toroid, one side of the skein passes through the core aperture and the other is outside the core. One end of the wire is secured to the core and the skein is'moved like an endless belt in the direction to tend to pull this end oif the core and wind it onto the skein.

As the tension increases in thelength of wire that extends fromthe skein to the core, the adjoining turn on the skein is released from the skein supporting means. Continued beltwise motion of the skein transfers the 'ice wire to the core, one turn for each complete revolution of the skein. The number of turns wound on the core for each turn taken off the skein is the ratio of the length of wire in one skein turn to that in one turn on the coil being wound. Thus, a relatively large number of turns may be wound on the core from a small number of turns in the skein.

For winding coils on the core of a dynamoelectric machine, each side of the skein may be made to pass through the space where the respective side of the finished coil is to lie. Successive turns on the skein are released alternately from the ends of the skein and drawn up against the core, between the ends of the slots. Since the wire need not be laid into the slots laterally as in conventional windings, the slot openings, i.e., the gaps between the faces of adjacent teeth, may be made as small as desired or omitted entirely. As in the case of toroids, the core openings may be wound substantially full without hand finishing, because the only thing that passes through the opening is the wire remaining to be wound in it.

The invention will be described with reference to the accompanying drawings, wherein:

Fig. 1 is a plan view of a preferred embodiment of the invention in a toroid winding machine,

Fig. 2 is a front elevation, partly in section, of the structure of Fig. 1,

Fig. 3 is a sectional view of a part of the machine, showing the operation of the resilient wire guiding fingers as the winding of a toroid approaches completion,

Fig. 4 is a section in the plane 4-4 of Fig. 3,

Fig. 5 is a section in the plane 5-5 of Fig. 2,

Fig. 6 is a top view of a portion of the machine showing the beginning of the operation of releasing a turn of wire from the skein,

Fig. 7 is a front view of the part shown in Fig. 6, showing a later stage in the operation,

Figs. 8, 9 and 10 are perspective views showing successive stages in the operation of winding a turn of wire ona toroid core,

Fig. 11 is a'perspective view of a modification of the device of Fig. 1 adapted to wind stator coils,

Fig. 12 is an end view of a stator core in the process of being wound,

Fig. 13 is a section in the plane 13-13 of Fig. 12,

a Fig. 14 is a perspective view of a further modification adapted for stator winding,

Fig. 15 is a section of the upper part of the machine ofFig. 14, showing the pulley supporting and wire tensiomng means,

Fig. 16 is an enlarged section of a portion of the pulley shown in Fig. 15, indicating the operation of releasing a wire, and

Fig. 17 is a face view of a skein-supporting pulley that may be used in the machine of Fig. 14. j 7 Referring first to Figs. 1 and 2, a pair of drums or pulleys 1 and 3 are disposed adjacent the upper surface of a base plate 5 for rotation about respective .vertical axes, and are adapted to support between them an open skein 7 of wire or other strand material that is to be wound on a toroidal core 9. The drum 1 is mounted loosely at the upper end of a shaft 11, so that the shaft and the drum may rotate with respect to each other. The shaft 11 is arranged to be driven as through gearing 17 by a motor, not shown. A friction disc 13 is splined or otherwise connected to the upper end of a shaft 11 to permit it to move axially of the shaft 11 while remaining in rotary engagement therewith. A spring 15 is arranged to press the disc 13 against the upperrsurface of the drum, thus providing a slip-clutch connection between the shaft 11 and the drum 1.

The second drum 3 is an idler, to be driven only by belt-like action of the skein 7. It is mounted on a shaft 18 that extends through a slot in the base plate and is supported in a block 19. The block 19 is supported on ways for movement toward and away from the drum 1. A spring 20 urges the block 19, and with it, the drum'3, away from the drum 1 so as to maintain the skein 7 under tension.

An inverted trough-like member 21 of approximately semicircular cross section extends between and over the drums 1 and 3, and is rounded at one of its ends as shown at 22 to merge smoothly into an edge that conforms with the periphery of the disc 13 and drum 1 throughout the approximately semicircular are on the side remote from the drum 3. The other end of the member 21 is provided with a plurality of curved spring fingers 23 adapted to maintain contact with a generally hemispherical part 25 secured to or integral with the drum 3. The spring fingers 23 permit the lateral motion of the drum 3 necessary to maintain tension in the skein 7. It will be apparent w thout further illustration that the axis of rotation of the drum 3 could be fixed, and the tension provided by an additional idler pulley between the two drums. In such an arrangement, the right hand end of the trough member 21 could be made like the other end, to conform to the upper edge of the drum 3.

A guide bar 27 is supported by a bracket 28 adjacent the upper surface of the inverted trough member 21, as shown in Figs. 2 and 5. A curved leaf spring 29 is provided at the left hand end of the bar 27 and extends down over the surface 22, diverging at its end as shown in Figs. 2 and 7, to permit the strand material being wound to enter between the spring 29 and surface 22.

Referring to Figs. 2 and 5, the toroid core 9 is supported between three approximately equally spaced rollers 30, 31 and 32. As shown in Fig. 5, the lower rollers 30 and 31 are secured to the base plate 5. The upper roller 32 is supported at one end of an arm structure 33 which is pivoted at its other end and biased by a spring 34 to hold the roller 32 against the core 9. Returning to Fig. 2, it will be seen that the arm member 33 is an assembly of two arms terminating at the respective ends of the roller 32 and joined together by a brace 35. The rollers 30, 31 and 32 may be made with cross sections that increase toward their ends as shown to resist sideways motion of the core 9 from tension in the strand being wound.

Referring to Figs. 3, 4 and 5, the trough member 21 is provided with an opening 36 to accommodate the core 9 and its Winding. A cylindrically arcuate shutter member 37. is supported inside the trough 21 as shown to cover the portion of the opening 36 that is not occupied by the Winding and core. A roller 38 is fastened near the'lower edge of the shutter to contact the outer surface of the toroid. As the diameter of the winding increases, the roller forces the shutter open as required.

As shown. in Figs. 1, 2, 6 and 7, a radially extending pick-off tooth 39 is provided on the disc 13. This tooth assists in separating the turn being wound from the remainder of the skein 7. Referring to Fig. 2 particularly, a pair of leaf spring hold-down fingers 40 and 41 are mounted as shown to extend over the skein 7 on respective sides of the toroid supporting assembly. The end of the finger 40 may be formed with its edge at a slight angle, as shown, to enable the strand to slide off smoothly when the tension increases during the winding cycle.

The operation of the above described structure is as follows. The toroid core 9 is manually inserted between the rollers 30, 31 and the roller 32. This is done by lifting the arm 35 and the shutter 37, dropping the core in place, then releasing the arm and the shutter. To load the skein 7 on the drums, one end of the wire to be wound is led by hand through the toroid and around both drums, then secured to the wire itself to form a single closed loop. The block 19 should be pushed to the left and held there during this operation, and released after several turns of wire are wound into the skein.

After the initial closedloopj is made, the drum 1 is rotated in the direction to wind more wire on'the skein, i.e., in the clockwise direction as viewed from above. This rotation, which may be and preferably is effected by driving the shaft 11 (Fig. 2) is continued until a skein containing the desired amount of wire is built up. It will be seen that the skein can be wound directly off an ordinary spool of wire. When the skein is completed, the wire may be cut, and the free end of the wire in the skein is attached, leaving a suitable length of lead, to the core 9 at its upper side as shown in Fig. 2.

After the skein is wound and the wire end attached to the core 9, the driving means is energized to rotate the shaft 11 (Fig. 2) at a speed that may be determined by the size and tensile strength of the wire. The disc 13 rotates the drum 1 in such a direction as to pull the end portion 42 of the strand taut between the drums and the core, as shown in Fig. 2. When the tension in the strand portion 42 reaches a value determined by the adyustrnent of the slip clutch spring 15, the drum 1 stops. The disc 13 continues to rotate, carrying the pick-off tooth 39 around and under the strand portion 42, which extends to the top side of the core 9 and thus lies diagonally above the plane of the skein, as shown in Fig. 2.

As the tooth 39 continues to move around the periphery of the drum 1, it throws the strand off the topside of the drum and on to the curved surface 22, as illustrated in Figs. 6 and 8. Any tendency for the tension to change during this part of the cycle of operation is counteracted by the operation of the slip clutch.

After the tooth 39 passes its extreme leftward position, whence it is shown in Fig. 6, the strand is pulled up over the surface 22 and under the spring 29, as shown in Fig. 7. Thereafter the distance between the toroid and the point where the strand is coming off the skein decreases, the tension decreases and the drum 1 rotates with the disc 13. The skein as a whole rotates beltwise between the drums 1 and 3 while the strand slides over the trough member 21 as in Fig. 9, and slips up off the drum 3, over the dome 25 and forms a turn on the core 9. Finally, as illustrated in Fig. 10, the newly wound turn. is pulled up tight and the cycle is repeated.

As the winding progresses, the core may be rotated periodically by hand to distribute the wire around the circumference. However, it is preferable to rotate the core automatically. This may be done by driving the roller 31 slowly. Fig. 5 shows a suitable means, comprising a pawl 43 mounted on a pivoted arm 44 in engagement with a ratchet wheel 45 coupled to the roller 31. The arm 44 may be driven periodically, for example, one stroke as each turn is wound on the core, by means of an electrom-agnet 46. The electromagnet may be energized through a switch 47 mounted on the guide bar 27 (Fig. 2) with an actuating arm arranged to be tripped by the strand as it passes between the bar 27 and the inverted trough member 21. The impulses provided by the switch, or the motion of the armature of the magnet 46, may be utilized to operate a turn counter of conventional type.

It will be apparent that as the winding is built up on the core 9, the spring pressed roller 32 moves upward to accommodate the increased diameter. See Fig. 4. The shutter 37 also moves up, while continuing to act as a guide surface for the strand being laid on the top of the toroid.

Referring to Fig. 3, the opening through the toroid gradually becomes smaller as the winding progresses. lifting the part of the skein passing through it up out of the plane of the drums 1 and 3. The hold-down fingers 40 and 41 keep the skein as a whole except in the region of the core. When the tension increases in the part of the strand next to be wound, as shown at 42 in Fig. 2, that part of the strand will slip out along and over the slanted end of the finger 40, separating itself from the .body of the skein and allowing the pick-off tooth to get :under it. Similarly, when a turn is nearing completion,

dash line 42 in Fig. 11.

' alternately from one drum and then the other.

as shown in Fig. 9, the hold downfirigerrfl will release the strand under tension. Since the number of turns remaining in' the skeinwill decrease as the winding nears completion, the size of the aperture remaining in the center of the toroid may be very small and the core may be wound substantially full. A modification of the above described machine, similar in design and operating on'the same principles, may be used to wind coils in place on the stator of a dynamoelectric machine. Referring to Fig. 11, the stator core 48 to be wound is supported between the drums 1 and 3' with the respective sides of the skein 7 passing through the slots 49 and 50 wherein the respective sides of the completed coil are to lie. In effect, each slot is an open-' ing in' a ring-like core whose boundary is defined by adjacent polar projections. The inverted trough members 21 of Figs. 1-5 is omitted. Instead, a pair of wire guide devicesor feathers 51 and 52, which are shaped substantially as shown in Figs. 12 and 13, are placed on opposite sides of the stator core and secured as by screws 53.

The drum 1 is similar to the drum 1 of Figs. 1-5,

except that its associated driving member 13, which cor.-

responds to the friction disc 13 of Fig. 2, is provided with a dome 54. The dome 54 may be a hollow cap placed over the friction members 13', or may be an integral part thereof. In the latter case, the spring arrangement for pressing the members 13' against the drum 1' could be located on the lower side of the mechanism.

Thedrum 3' is similar to the, drum 1, being provided with a friction drive member 13" with a dome 54 and 'a pick-01f tooth 39'. Both drums 1 and 3' are driven like the drum 1 in Fig. 2. Hold-down fingers 40 and 40' similar to the hold-down finger 40 of Fig. 2, are provided between'the core .48 and the drums 1 and 3, respectively. i In the operation of the device of Fig. 11, the skein 7 may be formed as in the device of Figs. 1-5, 'by winding the wire on the drums. This method is essential if the stator slots are completely closed. If the slots are open as in the core 48 illustrated in Figs. 11 and 12, the skein may be prepared externally of the machine and placed on the drums by carrying one end through the central opening of the core, then sliding the skein sides laterally into the slots 49 and 50. Alternatively, the skein sides may beleft in the central opening and allowed to slide into the slots turn by turn as the winding operation progresses.

After the skein has been loaded on the drums, the drive mechanism is energized to rotate both members 13' and 13". As shown in Fig. 11, the end portion 42 of the strand extends from the core 48 to the drum 3. The tooth 39' will separate this part from the body of the skein, throwing a loop up and over the dome 54. Meanwhile, the tooth 39 associated with the drum 1' passes above the skein, which is held down by the finger 40. As the loop formed over the dome 54 passes over the top, the tension decreases and both drums start to rotate, pulling the loop ,up against the right-hand face of the stator core. The feather 52 guides the wire downward to clear the slot openings intermediate the slots 49 and 50 and form an end turn loop 55, as shown in Fig. 13.

When the loop 55 becomes tight, the tension increases in the portion of the strand next to be wound, lying between the core 48 and the drum 1'. This portion moves out from under the finger 40, as indicated by the I The tooth 39 separates the portion 42 from the remainder of the skein, carrying it around the dome 54 until it is pulled up over the top, forming a loop which is then drawn up against the left- 'hand face of the core 48. Thereafter, the cycle is re- .peated, laying the turns down 'in the slots 49 and t) Since, as mentioned above,.the skein may be formed in place" onthe'machine, the slotsmay be completely closed. Thus, it is possible to insulate the'slotswith tubular material and wind into the tubes.

A further modification of the invention is shown in Figs. 14-16. In this case, the skein supporting means are in the form of pulleys 56 and 57 that are split as shown in Fig. 15, where the two sides 58 and 59 cooperate to act as one pulley. The side 58 is mounted on a shaft 60 for both rotary and axial movement, and is urged to the right by a spring 61. The distance that it can move to the left is limited by a stop which can be set by a micrometer head 62. The side 59 is supported on a shaft 63 for rotary movement but not axial movement.

Referring to Fig. 14, the pulley 56 together with its associated mechanism shown in Fig. 15, is mounted on a U-shaped frame 64 which in turn is supported for vertical motion by a pair of guide rods 65 extending from uprights 66 on a base plate 67. Springs 68 urge the frame 64 upward.

The. pulley 57 is similar to the pulley 56, and is similarly mounted between the uprights 66. The shaft 63 of pulley 57 is arranged to be driven through gearing 69 by drive means such as a motor, not shown.

Referring to Fig. 17, either or bothsides 58 and 59 of the pulleys 56 and 57 may be formed of a plurality of radially extending spring fingers 70 that are adapted to yield independently of each other in response to tension in the strand at the bottom of the groove, as shown in Fig. 16.

In this operation of the machine of Fig. 14, the stator core 48 which is to be wound is supported as by means 71 between the pulleys 56 and 57. Feathers 51 and 52 are arranged to guide the wire and form end turn loops, as in Fig. 13. The skein 7 may be wound in place on the pulleys or .prewound and then placed on the pulley. The respective sides of the skein are passed through the slots tobe wound, as in the machine of Fig. 11. The'inner end of the strand is secured to the starting point of the winding on the core 48.

When the driving means is energized, the skein acts like a belt, driving the pulley 56 from the pulley 57 in the direction tending to wind the inside turn back on to the skein. As the tension increases, the strand escapes between the sides of the adjacent pulley and the loop is drawn up across the face of the core 48 on that side. When the loop is drawn up tight, the tension increases in the inner strand on the other pulley, and the action is repeated on that side. Thus, the turns are drawn up alternately on one side of the core and then the other until .the winding is completed. Like the structure of Fig. 11, the device 'of Fig. 14 is capable of winding closed slots or slots insulated by tubing, as well as open slots.

Since many changes could be made in the above constructionand many apparently widely diiferentembodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A machine for winding strand material on a ringlike core, comprising a pair of drums adapted to support a skein of the material to be wound, one end of the strand in said skein being aflixed to said core, means for supporting the core with the part of it to be covered by winding located between said drums, said means also supin the direction tending to wind the strand on to the skein, thereby producing tension in the portion of the strand that extendsbetween the core and the skein,

means cyclically engaging the strand portiontthat extends between the core and the skein lifting that strand portion up and over one of the drums, and resilient means for guiding the strand to maintain it in the skein, said guiding means being responsive to cyclical increases in said tension resulting from continued motion of the skein to release successive turns of the strand material from the skein.

2. Apparatus for winding wire on a closed core through an aperture in said core, comprising means for supporting a skein of wire with one side of said skein passing through said aperture, and one end of said skein wire being atfixed to said core in such a way that the afiixed end is substantially separated from the skein, said supporting means being entirely exterior of said aperture whereby only said skein side passes through the aperture, means for moving said skein like an endless belt in the direction tending to wind said Wire onto said skein, means cyclically engaging and lifting the wire end which is affixed to said core up and over said supporting means, and means adjacent said skein but outside said aperture tending to retain said wire in saidtskein, said last mentioned means being adapted to be displaced by tension in a portion of said wire extending from said skein to said core to release the turn of said skein adjacent said portion, thereby separating the turns from said skein in succession to be drawn up to said core by continued beltlike motion of said skein in said direction.

3. A machine for winding strand material on a closed core, comprising means for supporting a skein of the strand material with one side of said skein passing through said core, and one end of said strand material in said skein being ailixed to said core, said wire end being affixed in such a way that it is substantially separated from the skein, means for moving said side of said skein through said core substantially continuously in the direction tending to wind the strand onto the skein and thereby pass the entire skein repeatedly through said core, means adjacent said supporting means and entirely outside said core for guiding said strand material to retain it in said skein, said guiding means being responsive to tension in the'portion of said strand next to be wound on said core to release the following turn of said strand on said skein, and means cyclically engaging the released strand and carrying that strand up and over the skein supporting means, whereby continued motion of said skein transfers said strand material from said skein to said core turn by turn.

4. A machine for winding coils in place on a core of the type that is provided with separate openings to contain two respective sides of the coilto be wound, comprising means for supporting the core, means for forming and supporting an elongated open skein of wire with one sideof said skein extending through one of said openings and the other side of said skein extending through the other of said openings, the skein wire having one of its ends afiixed to the core, means for moving said skein belt-wise through said openings, thereby cyclically producing increasing tension in the portion of wire that extends from said supporting means to said core, guide means for holding said wire portion in said skein,.said guide means being yieldable in response to sufficient tension to release and separate successive turns of wire from said skein, and means successively engaging each released turn of wire and carrying it up and over said skein supporting means so that the Wire is eventually drawn through said openings and across the ends of said core between said openings by continued motion of said skein, said skein supporting means and said guide means being wholly outside said core openings, whereby only said skein passes through the space in said openings to be filled by winding.

5. A machine for winding coils in place on the core of a dynamoelectric machine, such core being of the type that .is provided with separate openings to contain the respective sides of the coil to be wound, comprising means for supporting the core, means for forming-and supporting an elongated open skein of Wire with one side of said skein extending through one of said openings and the other side of said skein extending through the other of said openings, the skein wire having one of its ends afiixed tosaid core, said supporting means comprising rotatable drums outside said openings, means for moving said skein belt-wise over said drums and through said openings in the direction to produce increasing tension in the part of the wire next to be wound on the core, resilient means responsive to said increase of tension to release and separate the respective follow ing part of said wire from said skein, and means rotating with said drums engaging the separated strand of Wire and lifting it up and over said drums so that the wire is drawn through said openings and across the end of said core between said openings by continued motion of said skein.

6. A machine for winding strand material on a ringlike core, comprising a pair of drums adapted to support a skein of the material to be wound, one end of the strand material in said skein being afiixed to said core, means for supporting the core with the part of it to be covered by winding located between said drums, said means also supporting the core in such a way that the portion of the strand material affixed to the core is parted from the rest of the skein and one side of the skein passes through the opening in said core means supporting said drums for rotation about respective substantially parallel axes, means including a slip clutch for driving one of said drums to move said skein belt-wise around said part of the core in the direction tending to wind the strand onto the skein, thereby producing tension in said portion of the strand that extends between the core and the skein, resilient guide means for holdingrsaid strand in said skein until thesaid tension reaches a predetermined value less than suflicient to cause slippage of said slip clutch, whereupon said strand is released by said resilient guide means, and means rotating with one of said drums engaging the separated strand of wire and lifting it up and over one of said drums so that the wire is drawn off said skein and onto said core, the tension in said strand portion after release of said strand from the skein being limited by slippage of said slip clutch.

7. A machine for winding strand material on a ringlike core, comprising a pair of drums adapted to support a skein of the material to be wound, one end of the strand material in said skein being afiixed to said core, means for supporting the core with the part of it to be covered by Winding located between said drums in such a way that one side of the skein passes through the opening in said core, means supporting said drums for rotation about respective substantially parallel axes, a radially extending pickott' finger adjacent the periphery of one side of one of said drums and means rotatable about the axis of said drum supporting said pickoff finger to intercept the portion of the strand that extends between the core and the skein and lift the adjacent portion of said strand off said drum, means for driving said drum to move said skein beltwise around said portion of the core in the direction tending to wind the strand onto the skein, thereby producing tension in said portion of the strand that extends between the core and the skein, and resilient guide means for holding said strand in said skein and out of the path of said pickofi finger until the said tension reaches a predetermined value, whereupon said strand is released by said resilient guide means for engagement by said pickoff finger and removal from said skein.

8. A machine for winding strand material on a ringlike core, comprising a pair of drums adapted to support a skein of the material to be wound, one end of the strand material in said skein beingtaflixed to said core, means for supporting the core with the part of it; to be covered 9 by winding located between said drums in such a way that one side of the skein passes through the opening in said core, means supporting said drums for rotation about respective substantially parallel axes, means rotatable about the axis of said drum supporting a pickoif finger adjacent the periphery of one side of one of said drums, means for rotating said pickofi finger supporting means about its axis, said pickofi finger extending generally radially from said axis so as to intercept a portion of the strand drawn taut between the core and the skein and lift the adjacent portion of said strand 0E said drum, means including a slip clutch for driving said drum to move said skein belt-Wise around said portion of the core in the direction tending to wind the strand onto the skein, thereby producing tension in said portion of the strand that extends between the core and the skein, and resilient guide means for holding said strand in said skein and out of the path of said pickofi finger until the said tension reaches a predetermined value, whereupon said strand is released by said resilient guide means, the tension in said strand portion during rotation of said pickoff finger after release of said strand portion being maintained at a value limited by operation of said slip clutch.

References Cited in the file of this patent UNITED STATES PATENTS 751,816 Strong Feb. 9, 1904 1,437,685 Scharpenberg et a1. Dec. 5, 1922 2,596,520 Barker May 13, 1952 2,738,136 Bugg Mar. 13, 1956 2,807,425 Kent Sept. 24, 1957 FOREIGN PATENTS 503,525 Germany Feb. 24, 1929 599,992 Germany July 16, 1934 718,295 Germany Mar. 9, 1942 594,091 France June 13, 1925 160,098 Australia Dec. 2, 1954

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