US2541729A

US2541729A - Apparatus and method for making separable fasteners

Info

Publication number: US2541729A
Application number: US680485A
Authority: US
Inventors: Nicholas A Wahl
Original assignee: Wahl Brothers
Current assignee: Wahl Brothers
Priority date: 1946-06-29
Filing date: 1946-06-29
Publication date: 1951-02-13
Anticipated expiration: 1968-02-13

Description

Feb. 13, 1951 2,541,729

APPARATUS AND METHOD FOR MAKING SEPARABLE FASTENERS N. A. WAHL A A w. w w v w v I I I I '1 INVENTOR. NI C HQLA S A.

Patented Feb. 13, 1951 UNITED STATES PATENT OFFICE Nicholas A. Wahl, New York, N. Y., assi'gnor to Wa'hlB'rothers, New'York, N. Y., a partnership ApplicationJ-uneZS, 1946,.SeriaLNo; 680,485

16 Claims. 1

This invention relates to a method and. appa. ratus for making separable fasteners, particularly separable fasteners having loopsof coils as the interlocking elements;

separable fasteners wherein the interlocking elements are individual loops of continuous elon.- gated coils of' roughly heliccidal form have. cer tain advantages in the way of flexibility, appearance and low production cost not possible to attain with the older types. of. separable fasteners wherein the interlocking elements are rows of separate links or: teeth, usually of. metal, having hooks and eyes or other engagingdevices formed in the ends thereof. Coils. for use in separable fasteners are generally fashioned from continuous filaments of. metal or plastic.

In making coils for separable fasteners, it. has been suggested to wind. twov filaments simultaneously inopposite. directions and with alternating. turns. or loops on the same mandrel and subsequently to treat them while nested to. fix them in permanently coiled form, and thus to. form two cooperating coils-of the fastener at the same time. Although coils for. separable. fasteners have beenm'ade in this fashion and. used with a certain degree of satisfaction, the. method as practiced heretofore leaves much to be desired in certain respects. Thus it is known. that for best results, i. e., for greater. ease of aligning. the. engaging. portions of the loops properly and for providingv room for attaching. the coils to. fabric by sewing through each individual loop, eachloop should, when viewed along the longitudinal axis of the coil, be non-circular, e. g., it should be. somewhat ovoidor elliptical in outline. Such. coils are frequently referred to as being. oblong. in. cross-section.

. Filaments which have; been. used have usually been those whose. cross sections. have one diam.- eter greater than another. Onev such filament. has a cross-section resembling that of a finger ring. wherein. the inner surface is plane. or con.- cave and the outer. surface is convex. Suchfilaments may be wound on a mandrel to form. coils with the planeor. concave surface on the. inside of the coil. In suchcases the individual. loops of each coil are twisted and pressed out of round so as to accommodate between two of them a loop. of a similar but oppositely wound coil. Insome instances, particularly inthe case of a. roundfilament, notching orv indenting of the filaments. where they cross one another may be affected. The formation of a pair of cooperating coils wherein each individual loop of each. coil. has. the above desired characteristics isdifiicult to 2. attain when. a pair of. filaments is wound on a single-mandrel.

It is therefore, anobject of the present inven tion to provide a methodfonpreparing. elongated, flexible coils useful. in. the construction of. separable fasteners.

Another object is to provide amethodfor forming a pair of elongated coils adapted to be sepa'rably joined longitudinally and released with a slider.

An: additional. object is to. provide a method for fabricating a pair of interlocking coils useful. in the separable. fastener; art.

An. additional: object is to: provide. a method for fabricating simultaneously and continuously from a pair. of. plastic filaments a pair of interlocking coilsuseful in the construction. of a separable fastener.

Arr. additionalobiect. is. to provide'a method for making a separable: fastener wherein the inter.- locking elements. are the loops of a. pair of co operating coils. I

An additional object is to. provide. apparatus for forming. a separable fastener wherein the interlocking elementszare; individual loops of. pair of: continuous elongated. coils.

Still an. additional. object is. to provide appara tus for: preparing a pair of coils useful in the fabrication. ofa. separable: fastener;

An additional; object. is to provide apparatus formaking. simultaneouslyandi continuously from a pair of. plastic filaments. a. pair. of interlocking plastic coilsuseful in the. fabrication of a sep" arable fasteners These and related objects are accomplished readily by'wi ndi-ng simu ltaneously'two coil-form..- ing filamentsof metal, synthetic resin,- or of other suitable materialin opposite directions and: in alternating loops around an elongated primary stationary mandrel or pin in suchfashion: that each loop or convolution of one coil nestles between adjacentloops' of the other coil. In addition to the primary mandrel a pair of flexibletravel'i'ng mandrels are provided substantially parallel with and on opposite sides of the primary mandrel and in suchposition that one of the filaments is woundaround both theprimary stationary mandrel and one ofthe traveling man-- drels during'the formation of a single loop from the filament and the otherv filament is wound around. both the primary'stati'onary mandrel and the. other traveling. mandrel" during the formation of a. single. loop from the said other filament. two interlocked coils of filament; which are carried along by the traveling mandrels; slide off .the unsupported end of the primary stationary mandrel.

The coils are treated, either before or after leaving the primary stationary mandrel, in suitable manner to fix or set the filaments in the form of flexible, elongated coils which are then conveyed by the fiexible traveling mandrels to a windup reel for storage or cut into desired lengths and assembled in a suitable tape for use in a separable fastener. The traveling mandrel may be left in the sections of coils to assist in the assembly of the coil in a'tape, if desired, or the coil may be continuously unwound from the section of traveling mandrel or the latter may be pulled longitudinally from out sections of the coil.

The primary stationary mandrel, which may be of circular, elliptical, oval or of other suitable cross-section, is provided at its base, with an en larged sloping shoulder, which may conveniently be the formed end of the prmary stationary mandrel support, but which is preferably non-circular in cross-section, the filaments being wound in sliding contact over the shoulder in such manner that they slide from the shoulder onto the mandrels, each new loop formed thus being slid into pressure contact with the last preceding loop of the other coil as it is drawn tightly around the mandrels. The process may thus be carried out continuously, the formed interlocking coils sliding or traveling along the primary stationary mandrel away from the shoulder and being subsequently treated as hereinafter described. As one coil-forming filament is wound around the primary stationary mandrel, it is also caused to include within its convolutions one of the traveling mandrels but passes between the primary stationary mandrel and the other traveling mandrel, while the other coil-forming filament, as it is wound around the prmary-stationary mandrel in the opposite direction is caused to include within its convolutions the other traveling mandrel but not the first.

The traveling mandrels, which may be fashioned from a flexible metal wire, "a plastic filament or a fibrous cord' or string, need not clear the sloping shoulder of the primary stationary mandrel support as they approach the primary stationary mandrel but may slide over it in their travel. Due to the flexible nature of the travelng mandrels, the latter can be displaced easily by a coil-forming filament drawn between the shoulder and the traveling mandrel to allow the filament to slide over the shoulder and under the mandrel. Upon tightening the coils of filament on the mandrels, each of the traveling mandrels is gripped, tightly between the two series of loops and the latter are carried along by the traveling mandrels.

The coiled structure formed on the three mandrels thus consists of nesting alternate loops of the two coils 'with' the primary stationary mandrel passing through the loops of both .coils and with each of the traveling mandrels passing through the loops of one coil but not through the loops of the other. The primary stationary mandrel usually need be only long enough to insure proper forming of the two filaments into properly spaced coils, the traveling mandrels serving to keep the interlocked coils in proper alignment thereafter. A supply of each of the two coilforming filaments, usually on, spools, is carried in proper order around and between the mandrel supports, the filament passing through a tensioning device, which may be of any suitable sort, on its way to the mandrels.

In a preferred embodiment of the invention, a pair of secondary Stationary mandrels are also provided each of which is positioned close alon side a traveling mandrel and extends from the region where a filament is wound thereon in the direction of travel of the traveling mandrel for a short distance, e. g., for a distance approximately equal to the length of the primary stationary mandrel. Such secondary stationary mandrels increase the size of the longitudinal openings between the two series of loops over that caused by the traveling mandrels alone and this has certain advantages. Thus in case it is desired to leave the traveling mandrel in a coil when it is assembled in a tape, the use of a secondary stationary mandrel when forming the coils provides extra space to accommodate threads used in securing the coil to a tape. Also, when it is desired to draw the traveling mandrels longitudinally from a section of the interlocking coils without separating the coils preliminary to assembling the coils in a pair of tapes without utilizing the traveling mandrels, the operation is facilitated greatly by the extra room provided by the use of secondary stationary mandrels when forming the coils. The secondary stationary mandrels may extend into the zone where the filaments are treated to fix them in coiled form but it is not essential that they do so.

The secondary stationary mandrels may consist of a pair of metal wires or plastic filaments or may be made of other suitable material. The secondary stationary mandrels are positioned on opposite sides of the primary stationary mandrel and have at least their forward sections, with respect to the direction of travel of the interlocking coils thereon, parallel to the primary stationary mandrel, each of such sections lying in close sliding contact with a traveling mandrel. The parallel sections of the secondary stationary mandrels are each spaced from the primary stationary mandrel a distance at least substantially as great as the lateral thickness of the filament in one of the loops of the coils.

The supported end of each of the secondary stationary mandrel is inclined at an angle for a short distance away from the primary stationary mandrel and its support, and thus serves as a sloping guide to assist in guiding one of the coil-forming filaments into proper position on the mandrels and also to provide space for the other coil-forming filament to pass between it and the sloping shoulder of the primary stationary mandrel support onto the primary stationary mandrel. When using secondary stationary mandrels as described each loop of one coil is caused to enclose the primary stationary mandrel and one of the traveling mandrels together with the corresponding secondary stationary mandrel, while each loop of the other coil is formed around the primary stationary mandrel and the other traveling and secondary mandrels.

The formed structure consisting of the two interlocked coils is then treated while still on at least the traveling mandrels, to cause the filaments to assume permanently their coiled form. In the case of metal coil-forming filaments, the filaments may, depending upon the properties of the metal or alloy used, be sufiiciently fixed during the process of winding under tension so that further treatment is unnecessary. In other instances, a modified heat treatment of the metal coils may be desirable to further fix them in the desired shape and to temper them. In the case of interlocking coils made from thermoplastic filaments, e. g., from filaments of. polyamides,

chloride, cellulose acetate, polystyrene or rubber,

the structure is usually heated just suificiently' to relieve the strain in the coiled filaments but not sufficiently to cause appreciable softening of the plastic substance, and then cooled. Filaments made from a partially polymerized thermosetting resin may be heated on the mandrels to complete polymerization of the resin. The trave1 mandrels should, of course, be unaffectedby the heating or other treatment.

In certain instances, it is advisable to lubricate the filaments or the stationary mandrels, orboth, to promote easier sliding of the coils therealong. Soap, oil, parafiin or other substances non-reactive with the mandrels or coil-forming filaments may be used as lubricants. If desired, the primary stationary mandrel may" be adjustabl'y retractable into the primary stationary mandrel support and its effective length thus varied to adjust the frictional resistance tending to retard the sliding movement of' the coils along the mandrels, and thus to alter somewhat the spacing of the loops of the mandrels. During winding and subsequent treatment of the coils, bending and twistin? of the filaments is caused by the pressure of one convolution on another and this provides means for positive interlocking of the coils when assembled in a tape. Also, notching of the filament loops where. they cross one another may be caused to occur during the treating step, if desired. Such notchin'g is particularly desirable when the filaments are of circular cross section. The three mandrels should, of course, be constructed of material which will be substantially unaffected during the treatment to fix the filaments in coiled form.

Following the heating and cooling or other treatment of the interlocking coils, the structure is then conveyed on the traveling mandrels to a wind-up reel for storage or is immediately cut into appropriate lengths for assembling in a tape. The entire operation is conveniently carried out using a modified rotary braider as will be hereinafter described.

The apparatus and method of the invention may be understood clearly by reference to the following drawings wherein, for the sake of clarity, certain features are shown on a some.- what exaggerated scale and wherein.

Figure 1 is a side elevation of a. pair of oppositely wound interlocking coils. useful. in the separable fastener art.

Figure 2 is a diagrammatic view of' a rotary braider modified to carry out the process of the. invention, and

Figure 3 is an elevation, partly in section, or a primary stationary mandrel, two secondary stationary mandrels and two continuous, flexible,

as loop 353', is nested between two adjacent loops,

as 3! and 32, of the. other coil in. interlocking relationship. When each of the coils are assembled in suitable tapes which maintain the loops of each coil in fixed longitudinal relationship, the coils may be separably joined with a suitable slider in positive interlocking relationship andin such position. will. withstand a high.

degree of l'ateral' tension without separating.

Referring now to Figure 2,. there is shownin diagrammatic outline a modifiedrot'ary braider having a stationary table ll! with two tracks or races l i formed therein in which a pair of spool carriages l2 carrying spools M travel in opposite.

directions around a support i3 for a primary stationary mandrel, it of Figure 3. The primary stationary mandrel support is fixedly positioned in an upright position on the table HJ'. of the primary mandrel support is tapered, as shown clearly in Figure 3 to provide a sloping shoulder ii" for guiding a filament l5 wound in sliding contact therearound onto the primary stationary mandrel 8;

The primary stationary mandrel IB' is in. the

form of a short upright pin, which may be of" cylindrical, elliptical or other suitable cross-section, and which may be secured at one end to the center of the tapering shoulder i! in suitable manner. A. preferred modification comprises a primary stationary mandrel is which may be retracted into the shoulder i! and held in any desired position by conventional means, not shown. The effective length. of the primary stationary mandrel I8 may be varied considerably but it should be sufficiently long to accommodate.

at least two or three lo'ops'of' each soil. to insure their being formed in proper shape. The primary stationary mandrel is usually somewhat.-

rounded on its unsupported end to facilitate easy disengagement therefrom of' the sliding double coil structure.

A pair of mandrelguid'es l9, conveniently hollow posts mounted verticallyon table HI with idler pulleysv 2| at the top; are provided for guiding. a pair of flexible traveling mandrels 20. The flexible mandrel guides. [9 are located in such position with respect to the carrier races ii that one of thespools i i passes around the primary stationary mandrel support i3 and one. of the flexible mandrel guides iii as its carriertravelsin its race,

and the other spool passes around the primary stationary mandrel support andtheother flexible mandrel guide as its carrier. travels. in its race. A pair. of cords, Wires or other flexiblefilaments 20,,

may serve as flexible traveling mandrels and are supplied under tension to the mandrel guides I9 from spools or. reels located underneath the table it), but not shown in the drawing. These flexible traveling mandrels pass up through the hollow mandrel guides i9 and thence. over the sloping shoulder 51 of the primary mandrel supportinto and throughout the length of the coiled filaments.

Apair of spools is are carried by the. spool carriages l2 which are driven by conventional.

driving apparatus, not shown. Each of the spools it carries a supply of coil iorming filament. is

which, as it leaves its respective spool, passes through a filament tensioning device it, which is of conventional design and is usually spring loaded, and thence in sliding contact over the shoulder H to form a tight loop around the priaround the primary stationary mandrel support I3, which is not centered with respect to either of the races H. A flattened area 33' is advantageously provided on one side of the shoulder Fl where the two filaments l5 cross one another'just The top prior to passing between the shoulder l7 and the secondary stationary mandrel supports 35.

As each loop of a coil is formed by winding a coil-forming filament around the base of the primary stationary mandrel and the loop drawn tight, it lies in close contact with the preceding loop of the other coil. As each of the coil-forming filaments I is wound around the primary stationary mandrel 18, it also includes within each of its convolutions one of the flexible traveling mandrels but not the other. In the coiled structure thus formed, each of the flexible traveling mandrels lies within the convolutions of one of the coils, but not within the convolutions of the other coil, and the other flexible traveling mandrel occupies the reverse position with respect to the two coils. The flexible traveling mandrels are gripped tightly between the two coils when the loops are pulled tight and the traveling mandrels thus carry the nested coils along with them. Suflicient tension is maintained on the flexible traveling mandrels to prevent undue kinking of the mandrels and unnesting of the two coils.

The treatment of the interlocking coils on the traveling mandrels is, as mentioned previously, varied according to the nature of the substance from which the coil-forming filaments l5 are formed. Generally speaking, in the case of coilforming filaments of synthetic resin a simple heating, or heating and cooling, operation is sufficient. Heating may be effected by means of a circular hollow heater 22 of Figure 1, positioned around a short section of the coils on the traveling mandrels adjacent or removed from the tapered end of the primary stationary mandrel support, by high-frequency heating, or in any other convenient manner. A rheostat, not shown, may be provided to regulate the degree of heating. The degree of heating is regulated so as to relieve the strain within the coil-forming filaments but not to soften them appreciably. Cooling may be effected with a coiled tube 26 carrying cold water around the coils of filament immediately after they leave the heating zone, or in any other convenient way. In the case of metal coil-forming filaments a somewhat more drastic heat treatment of the coils may be necessary than is the case with plastic coil-forming filaments. Following the completion of the treatment to fix the filament in coil form the traveling interlocked coils on the traveling mandrels may be passed over an idler pulley Z3 and under a pulley 24 carrying a weight 25 to maintain the tension on the traveling mandrels and then wound up on a reel 2'! or cut into desired lengths for assembling in suitable tapes.

A pair of secondary stationary mandrels, 34 of Figure 3, may, as hereinbefore mentioned be provided, if desired, and each may conveniently be mounted on an arm 35 adjustably clamped, as by a set screw 36 of Figure 2 in a hole drilled at an angle through a post 37 mounted vertically on the table it]. The posts 37 are located near or adjacent to the guides ill for the flexible mandrels 23 in such position that one of the spools M as it is carried around the primary stationary mandrel support 53 and one of the flexible mandrel guides I9 is also carried around one of the posts 3'1, and the other spool is carried around.

A pair of wires or stiff plastic filaments may serve as the secondary stationary mandrels 34 and are secured at one end in any convenient manner to the secondary stationary mandrel supports. The secondary stationary mandrels 34 and their supports are arranged so that the forward section or unsupported end of each secondary stationary mandrel lies closely alongside a traveling flexible and at a short distance from and parallel to the primary stationary mandrel. Generally speaking, the distance separating the primary and a secondary stationary mandrel, and likewise the primary stationary mandrel and a traveling mandrel, will be substantially the width of the coil-forming filament so that the sceondary stationary mandrel and the traveling mandrel will lie together closely against one series of filament loops and the other series of filament loops will be drawn tightly over them. Secondary stationary mandrels having cross-sections of a desired shape and size may be employed to provide a longitudinal opening of desired shape and size between the coils in the finished structure.

The supported ends 38 of each secondary stationary mandrel and the adjustable arm 35 to which it is secured are inclined at an angle away from the primary stationary mandrel l8 sufficient to clear the sloping shoulder ll of the primary stationary mandrel support and permit one of the coil-forming filaments IE to slide between the two onto the primary stationary mandrel iii. The other coil-forming filament, which it wound outside the secondary stationary mandrel, is guided into its position around the secondary stationary mandrel by the sloping section 33 thereof and the sloping arm 35.

I claim:

1. In a method for forming a pair of coils for a separable fastener, the steps including; winding a tensioned coil-forming filament in one direction in a series of loops around a stationary mandrel and a tensioned flexible traveling mandrel; and simultaneously winding another tensioned coil-forming filament in the reverse direction around the stationary mandrel and another flexible traveling mandrel in a second series of loops alternating with the loops of the first series, each loop of the second series nestling between but not crossing adjacent loops of the first series and said flexible mandrels traveling on opposite sides of the stationary mandrel.

2. The method as claimed in claim 1 wherein the coil-forming filaments are metal filaments.

3. The method as claimed in claim 1 wherein the coil-forming filaments are synthetic resin filaments.

4. The method of claim 1 wherein the traveling flexible mandrels are continuous fibrous cords.

5. The method of claim 1 wherei the traveling flexible mandrels are flexible metal filaments.

6. The method of claim 1 wherein the traveling flexible mandrels are flexible plastic filaments.

'7. In a method for forming a pair of coils for a separable fastener the steps including: winding a tensioned coil-forming filament in one direction in a series of loops around a stationary mandrel and a tensioned flexible traveling mandrel; simultaneously winding another tensioned coil-forming filament in the reverse direction around the stationary mandrel and another tensioned flexible traveling mandrel in a second series of loops alternating with the loops of the first series, each loop of the second' series nestling between but not crossing adjacent loops of the first series and said flexible mandrels traveling on opposite sides of the stationary mandrel; and subsequently treating the formed coils to eifect fixing of the filaments in permanently coiled form.

8. The method. of claim 7 wherein the coilforming filaments are organic thermopastic filaments and the filaments are heated and subsequently cooled to effect fixing thereof in permanently coiled form.

9'.'In a method for forming continuously a pair of coiled elements for a separable fastener, the steps including: continuously winding a coilforming filament in one direction in a series of loops: around a stationary mandrel unsupported at. one end' and a continuous flexible traveling mandrel; simultaneously winding another tensioned coil-forming filament in the reverse direction around the stationary mandrel and another continuous flexible traveling mandrel in a second series of loops alternating with the loops of the first series, each loop of the second series nestling between but not crossing adjacent loo s of the first series and said continuous flexible mandrels traveling longitudinally on opposite sides of the stationary mandrel in a direction parallel with the longitudinal axis thereof and toward the unsupported end thereof; continuously sliding the formed nestled coils ofi the unsupported end of the stationary mandrel; and conveying the formed coils of filament on the traveling flexible mandrels continuously through a treating zone wherein fixing of the filaments in permanently coiled form is effected.

10. In a method for forming a pair of interlocking coils for a separable fastener, the steps including: winding a tensioned coil-forming fila ment in one direction in a series of loops around a primary and a secondary stationar mandrel and a tensioned, flexible traveling mandrel; simultaneously winding another tensioned coilforming filament in the reverse direction around the primary stationary mandrel and another secondary stationary mandrel and another flexible, traveling mandrel in a series of loops a ternating with the loops of the first series, said flexible mandrels traveling longitudinally on opposite sides of the stationary mandrel in a direct on parallel with the longitudinal axis thereof and toward the unsupported end thereof. and a section of each secondary stationary mandrel bein positioned parallel with the primary stationary mandrel and closely adjacent to a traveling mandrel; and conveying the formed coils of filament on the traveling flexible mandrels continuously through a treating zone wherein fixing of the filaments in permanently coiled form is effected.

11. In apparatus for forming a pair of interlocking coils for a separable fastener, the combination including: a stationary mandrel supported at one end on a mandrel support; two flexible traveling mandrels trave adjacent to on opposite sides of the stationary mandrel longitudinally in a. direction parallel with the axis thereof toward the unsupported end thereof; m ans for winding a tensioned coil-forming filament in a series of loops around the stationary mandrel and one of the flexible traveling mandrels; means for simultaneously winding another coil-forming filament in the reverse direction around the stationary mandrel and the other flexible traveling mandrel in a series of loops alternating with the loops of the first series; and means for treating the formed interlocking coils to fix them in permanently coiled form.

12. Apparatus as claimed in claim 11 wherein the support for the stationary mandrel is tapered immediately adjacent to the point of support of the stationary mandrel and adapted to slidably guide onto the base of the stationary mandrel a tensioned filament wound therearound.

13-. Apparatus as claimed in claim 11 wherein the support for the stationary mandrel is tapered and of non-circular cross-section immediately adjacent to the point of support of the stationary mandrel and adapted to slidably guide onto the base of the stationary mandrel a tensioned filament wound therearound.

14. Apparatus as claimed in claim 11 wherein the primary mandrel is adjusta-bly retractable into the primary mandrel support to provide means for adjusting the effective length of the mandrel.

15. In apparatus for forming a pair of interlocking coils for a separable fastener, the combination including: a support for a stationary mandrel; a stationary longitudinal mandrel supported at one end on the mandrel support; a sloping shoulder on the mandrel support immediately adjacent the base of the stationary mandrel adapted to slidably guide a tensioned filament wound therearound onto the stationary mandrel; stationary guiding means for a pair of traveling flexible mandrels located on either side of the support for the stationary mandrel; a pair of tensioned flexible traveling mandrels traveling from the flexible mandrel guides to points adjacent the base of a the stationary mandrel and thence in a direction away from the sloping shoulder parallel to the longitudinal axis of the stationary mandrel; means to carry a supply of a coil-form ng filament in one direction around the support for the stationary mandrel and one of the flexible mandrel guides; means to carry another supply of a coil-forming filament simultaneously in the reverse direction around the support for the stationary mandrel and the other flexible mandrel guide, each of the supply means being adapted to feed a coil-forming filament in sliding contact over the sloping shoulder of the mandrel sup ort in tight loops encircling the stationary mandrel and one of the traveling mandrels and alternating with loops of the other filament: and tensioning means for each of the coilforming filaments and for each of the traveling mandrels.

16. In a paratus for forming a pair of interlocking coils for a separable fastener, the combination including: a support for a primary stationary mandrel; a primary stationary longitudinal mandrel supported at one end on the primary mandrel support; a sloping shoulder on the primary mandrel support immediately adjacent the base of the primary stationary mandrel adapted to slidably guide a tensioned filament wound therearound onto the primary stationary mandrel; stationary guiding means for a pair of traveling flexible mandrels located on either side of the support for the primary stationary mandrel; a pair of tensioned flexible traveling mandrels traveling from the flexible mandrel guides to points adjacent the base of the stationary mandrel and thence parallel to the stationary mandrel toward the unsupported end thereof; separate supports for a pair of secondary stationary 1 1 mandrels; a pair of secondary stationary mandrels each supported at one end on a secondary mandrel support and each having a section thereof positioned parallel to the primary stationary mandrel and closely adjacent to a flexible traveling mandrel; means to carry a supply of a coilforming filament in one direction around one of the flexible mandrel guides and the supports for the primary stationary mandrel and for one of the secondary stationary mandrels; means to carry another supply of a coil-forming filament simultaneously in the reverse direction around the other flexible mandrel guide and the supports for the primary stationary mandrel and the other secondary stationary mandrel, each of the supply means being adapted to feed a coil-forming filament in sliding contact over the sloping shoulder of the primary mandrel support in tight loops encircling the stationary mandrel and one each of the traveling mandrels and secondary stationary mandrels and alternating with the loops of the 12 other filament; tensioning means for each of the coil-forming filaments and for each of the traveling mandrels; and means for treating the filaments on the traveling mandrels to set them in permanently coiled form.

NICHOLAS A. WAl-IL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 450,685 Struss Apr. 21, 1891 1,805,494 McCahey May 19, 1931 1,913,292 Schweiter June 6, 1933 2,343,348 Wahl Mar. 7, 1944 FOREIGN PATENTS Number Country Date 9,547 Great Britain May 24, 1900