CA1122786A - Fastener - Google Patents

Abstract

ABSTRACT
A method for forming strip material adapted to be cut into lengths to provide parts of fasteners is described. The method comprises the following steps: moving two non-fibrous polymeric strips from generally opposite directions around parallel arcuate spaced guides and away from the guides in the same direction along parallel paths; heating the polymeric strips on the spaced guides to soften them; feeding flexible, resilient polymeric monofilaments between the spaced guides from the sides thereof opposite said parallel paths and in a direction generally parallel to said parallel paths; alternately deforming the mono-filaments into a first line of U-shaped portions while pressing the first line of U-shaped portions into engagement with one of the strips and then deforming the monofilaments into another line of U-shaped portions while pressing the other line of U-shaped por-tions into engagement with the other strip to embed and bond the U-shaped portions of the monofilaments in the strips in the positions that they are pressed into engagement therewith so that lengths of the monofilaments between the U-shaped portions extend generally normally between the strips as the strips move along the parallel paths; severing the monofilaments midway between the strips to form two brush-like halves; and heating the newly severed terminal ends of the monofilaments projecting from the strips to form heads having generally hemispherical surfaces opposite the strips.

Description

~ 913,878 FASTENER
This invention relates to fasteners of the t~pe including two parts, at least one of which parts includes a field of headed pro~ectlons adapted to releasably inter-engage with the other part, and in one aspect to such fasteners in which both parts include an array of headed pro~ectlons which can be simultaneously engaged without regard to the relative angular relationship of the arrays.
The present invention provides an elongate strip material from which a length ma'y be severed that forms at least one part of a fastener, which strip material includes a back-ing supporting a multiplicity of headed pro~ections adapted to releasably engage a second part of the fastener. One length of the strip material may be used with a length of conventional fibrous material to form a fastener, or a fas-tener can be formed from two lengths of the strip material which has its pro~ections disposed in an array which affords firm simultaneous engagement of the pro~ections in any angu-lar orientation of the arrays on two lengths Or the strip material.
The present invention also includes a method for rapidly producing the strip material at substantially less cost than the cost to cast a similarly shaped part of a fastener. Also the method provides great versatility in the length and head size of the pro~ections and the arrays in which they are disposed as may be desired for specific applications of the strip material.

The strip material according to the present invention includes a backing comprising a uniform non-fibrous polymeric bonding layer of a predetermined thickness and having an exposed major surface, and a multiplicity of flex-ible resilient monofilament portions deformed into U-shaped elements of longitudinally oriented polymeric material of a di-ameter less than said predetermined thickness, each U-shaped element including a central bight portion embedded in, bonded in and held only by said bonding layer, each U-shaped element also including two straight stem portions of essentially the same length extending in the same direction from the opposite ends of said bight portion, projecting generally normal to said exposed major surface of the surface bonding layer and having unsupported ends opposite said bight portion, each U-shaped element also including an enlarged generally hemispherical head at each unsupported end, each of the heads being generally concentric with its supporting stem portion, having a cam surface opposite its supporting stem portion adapted for engagement with the cam surfaces of heads along a different portion of the strip material to produce deflection of the stem and movement of the heads on the stems past each other upon movement of the heads toward each other with the portions of the backing behind the heads generally parallel, and having a surface opposite said cam sur-face which is generally planar and extends at generally a right angle from its supporting stem portion adapted to engage a similar surface on another head, the bight portions of said U-shaped elements being disposed generally parallel with a plurality of groups of the bight portions each being disposed generally side by side to form a plurality of generally parallel rows of stem portions with said heads along and between the rows ~12~786 being spaced at distances which, as an average, are generally no greater than the diameter of the heads so that simultaneous movement of all the heads of different portions of the strip material past each other can occur only upon resilient separation of many of said heads, with said stems being spaced apart a dis-tance which, as an average, is at least as large as the diameter of said heads to afford positioning of the heads of one portion of the strip material between the stems of another portion of the strip material and with the length of each stem portion from the major surface to the head on its unsupported end being at least - equal to the diameter of the head to afford deflection of the stems to allow simultaneous movement of all the heads of different portions of the strip material past each other at any relative angular orientation between the rows of stems of the portions.
According to another aspect of the invention, there is provided a method for forming a strip material adapted to be cut into lengths that provide parts of fasteners, wherein said method comprises the steps of moving two non-fibrous polymeric strips from generally opposite directions around parallel arcuate spaced guides and away from the guides in the same direction along parallel paths; heating the polymeric strips on the spaced guides to soften them; feeding flexible, resilient polymeric monofilaments between the spaced guides from the sides thereof opposite said parallel paths and in a direction generally parallel to said parallel paths; alternately deforming the monofilaments into a first line of U-shaped portions while pressing the first line of U-shaped portions into engagement with one of the strips and then l~ZZ786 deforming the monofilaments into another line of U-shaped portions while pressing the other line of U-shaped portions into engagement with the other strip to embed and bond the U-shaped portions of the monofilaments in the strips in the positions that they are pressed into engagement therewith so that lengths of the mono-filaments between the U-shaped portions extend generally normally between the strips as the strips move along the parallel paths;
severing the monofilaments midway between the strips to form two brush-like halves; and heating the newly severed terminal ends of the monofilaments projecting from the strips to form heads having generally hemispherical surfaces opposite the strips.
In a specific embodiment described longitudinal striking bars disposed generally transverse of the monofilament paths engage the monofilaments and carry out the deforming and pressing steps.
Where the strip comprises a surface bonding layer of a heat softenable material, it may be heated on th~ guides until the bonding layer is sufficiently soft that the U-shaped lengths of the monofilaments will be embedded in the bonding layer by the striking bars. Alternatively the monofilaments may be bonded by coating the strip with a bonding layer of adhesive onto which the U-shaped segments are pressed.

- 3a -l~ZZ786 Whenthe polymeric materlal of the monofilaments is the same as the materlal of a heat softened bondlng layer into which the monofilaments are pressed, the mono-filaments can be caused to fuse in the bondlng layer so completely that in some cases portions of the monofilaments are hard to separately ldentify from the material of the bondlng layer.
With this method of production the spacing between the stems transverse of the strip can be controlled by the spacing between the monofilaments being fed between the arcuate guides. The spacing between the stem portions of the U-shaped lengths of monofllament are controlled by the thicknesses of the blades which press the filaments against the strip. The spaclng between palrs of rows of the stems longltudinally of the strlp is controlled by the timing relatlve to the speed of the strip at which the blade presses the monofilaments into engagement therewith.
Also the lengths of the stems are controlled by the spacing between the strips along their parallel paths and the diameter~ of the heads formed on the~ stem portlons are controlled by the amount of heat applied to the stems.
By this production method the rows of stems can be dlsposed ln a rectangular array with the cross rows and longitudinal rows respectively normal and parallel to the edges of the strip~ and with all of the stems equally spaced along each row. Wlth such an even rectangular array, however 3 it has beenfound that the heads of the parts engage most securely when the rows of stems of the two parts are disposed at some angle to each other as opposed to being parallel, thls being partlcularly true with respect to shearing of the parts in directions parallel to thelr backings and to ~e rows. Thus it may be desirable to do one or more of the followlng: (1) vary the spaclngs Or the stems along the rows extending longitudinally of the strip by llse o~ the technlques described above so that at least when the rows of two parts wlth such varled spacing are engaged at right angles to each other a greater sepa-rating and shear strengths will be developed, (2) dispose the rows o~ U-shaped filaments so that their stems are not aligned normal to or parallel with the edges of the strip so that when a user engages two parts cut from the strip with their edges aligned (as he would normally be expected to do) the rows on the parts will cross each other to develop the maxlmum strength in the fastener both in tension and shear (this can be done by orienting all or portions of the striking bars at an acute angle with respect to the edge Or the strip movingthrough the tacking station), or (3) shift successive rows of U-shaped ~ilaments slightly in a direction transverse of the strip so that the stems of successive rows will not be aligned and thus will not permit shearing longi-tudinally of the strip (this can be done by varylng the position of the spaced filaments fed to the tacking station transversely of the strip).
The stem portlons in the U-shaped monofilaments must be sufficiently long and ~lexlble so that upon engage-ment of the parts the heads on each part can move to flnd spaces between the heads on the other part and permit slmul-taneous movement of the head~ past each other ln any ~lZZ786 orlentatlon of the row~ of stem~ of the parts relative ~o each other. To permlt such movement the stems should have a length whlch is at least equal to the maxlmum dlameter of the head, and preferably ln the range of about 2~1/4 to 3 tlmes the maximum diameter of the head.
The lnventlon wlll be further descrlbed wlth reference to the accompanylng drawlng wherein like numbers refer to like parts in the several vlews, and wherein:
Flgure 1 ls a plan vlew of one of the parts of a fastener made from strip material according to the present lnvention;
Flgure 2 is an enlarged fragmentary vlew in perspective of the part of Flgure l;
Figure 3 is an enlarged sectlon taken approxl-mately along llne 3-3 of Figure l;
Flgures 4 and 5 are both slde views showlng the fastener accordlng to the present invention wlth its parts engaged whlch lllustrate two dif~erent orientations of the rows of pro~ections durlng engagement;
Figure 6 ls a schematic vlew lllustrating a method according to the present lnvention for making strip materlal from whlch the part of Flgure 1 is cut;
Flgures 7, 8, 9 and 10 lllustrate alternate embodlments of the strip materlal according to the pre~ent lnventlon; and Flgure 11 lllustrates an alternate embodiment of a fastener ln whlch a length Or the strlp materlal accord-lng to the present lnventlon can be used.
Rererrlng now to Flgures 4 and 5 of the drawlng, ~ZZ786 there is lllustrated a fastener 10 which comprises two identical parts 11 (one of which is illustrated in Figures 1, 2 and 3), which are lengths severed from strip material 24 according to the present invention.
Each part 11 includes a backing 12 comprising a non-fibrous polymeric bonding layer 15 in which ls bonded a plurality of flexible resilient generally U-shaped mono-filaments 13 (Figures 2 and 3) of longitudinally oriented polymeric material. Each monofilament 13 comprises two stem portions or stems 14 pro;ecting at generally a right angle from an exposed ma~or surface of the bonding layer 15 and extending from the ends of a bight portion 17 of the monofilament 13. As can be seen in Figures 2, 3 and 4, the bight portions 17 in each part 11 lie generally parallel to and are embedded in the material of its bonding layer 15.
A generally hemispherical head 18 is formed at the free end of each stem 14. The heads 18 have arcuate generally semi-spherical cam surfaces 20 opposite the backing 12 adapted for engagement with the cam surfaces 20 on the heads 18 of the other part 11 to produce the necessary side deflectlon oP the stems 14 upon movement of the heads 18 toward each other with the backings 12 generally parallel so that the heads 18 may simultaneously pass to engage the parts 11 in the manners illustrated in Figures 4 or 5. Also the heads 18 each have a generally planar latching surface 21 eXtendinK
radially outwardly of the stem 14 and adapted to engage the latching surface 21 on one of the heads 18 of the other part 11 to retain the engaged heads 18 ln engagement until a predetermined force i5 applied to separate the parts 11.

l~ZZ786 Slnce engagement of the latchlng surfaces 21 do not produce as much camming actlon as engagement of the cam surfaces 20, the configuration of the heads 18 desirably requlres a force to engage the parts 11 which is not much larger than the force requlred to separate them.
The monofilaments 13 are bonded to the backing 12 with their bight portions 17 parallel to each other and to parallel edges 19 of the backing 12. The bight portions 17 of groups of the monofilaments 13 are disposed side by side to form a serles o~ generally parallel rows, with each row of monofilaments 13 providing two corresponding rows of allgned stem portions 14 and heads 18 which are disposed generally normal to the edges 19.
The stem portions 14 on each U-shaped monoflla-ment 13 and the ad~acent stem portions 14 along the rows(i.e. in a direction normal to the length of the bight portlons 17 and to the edges 19) are spaced apart so that the head 18 of another monofllament 13 may be positioned therebetween wlthout substantially spreading the stems 14.
The heads 18 on these stems 14, however, are spaced apart a dlstance less than their own diameter so that a head 18 on a mating part 11 may only move therebetween upon separa-tion of the heads 18 by resilient deflection of the stems 14.
The heads 18 of ad~acent rows of the U-shaped monofilaments 13 are spaced apart a distance somewhat greater than the distance between the heads 18 of each U-shaped monofilament or the dlstance between ad~acent heads 18 along each row to provide the aforementioned advantage wlth respect to the shear strength of the ~3.z278~i g fastener 10. This larger spacing is experlmentally deter-mined so that it is sufficient to afford movement of the heads 18 on each of the parts 11 simultaneously past each other wlth the backings 12 o~ the parts 11 maintained par-allel to each other and with the rows of U-shaped monofila-ments 13 in any relative angular orientation. This spacing, however, is generally nog~eater than that required for such engagement so as to provide the maximum disengagement force for the parts 11.
In addi~ion to the surface layer 15, the backing 12 as illustrated includes a layer of pressure sensitive adhe-sive 22 on the surface of the bonding layer 15 opposite the U-shaped monofilaments 13, and a removable release llner 23 over the layer of adhesi~e 22. The layer of adhesive 22 affords firm adhesion of the parts 11 to rigld surfaces to be releasably ~oined thereby.
Figure 6 schematically illustrates a method according to the present invention for contlnuous forming Or the strip material 24 from which may be cut desired lengths to provide the parts 11. Two strips 26 of heat softenable polymeric materlal to be lncorporated as the bondlng layer 15 ln the backing 12 extend from generally opposlte directlons from supply rolls 27, each extending from the supply roll 27 around a guide roller 28 mounted vla a frictlon clutch to provide a desired tension in the strip 26. From the guide roller 28, each strlp 26 passes onto an endless support belt 29 (such as of aluminum) extend-ing around the arcuate surface 30 of a platen 31 heated to a temperature adapted to soften the polymeric strlp 26 and ~lZ;Z786 between one cushion belt 32 of a commerclal extruslon take-off devlce 33 (e.g. a Model No. 3-650-VT as manufactured by Teledyne Farris Eng. Co. Palisades Park, New Jersey). The portions of the support belts 29 passing around the ad~acent ends of the heated platens 31 provlde arcuate spaced parallel support surfaces around which the strips 26 are moved onto parallel paths between portions of the support belts 29 passlng between the cushion belts 32 of the take-off device 33.
A plurality of flexible resilient monofilaments 36 are guided between the ad~acent ends of the platens 31 by a guide 37 comprislng a plurallty of small parallel side by side evenly spaced tubes through each of which one of the monofilaments 36 is positioned. A pair of longitudinal striking bars 39 are mounted on opposite sides of the path for the monofilaments with each one belng mounted for reciprocal motion in a guide 40 by activatlon of a driving means such as an air cylinder 41 between a retracted posi-tion (shown for the upper striker bar 39) spaced from the monofilaments 36, and a pressing position (shown for the lower striker bar 39) at which an end surface 42 on the striker bar 39 presses the monofilaments 36 into the softened polymeric strip material 26 on the support belt 29 along the curved surface of the heated platen 31. The end surfaces 42 Or the strlker bars 39 are convex to match the ad~acent contour of the platen 31, have a width sufficient to contact all of the monofilaments 36 guided between the platens 31, and have thicknesses adapted to form U-shaped lengths of the monofilaments 36 having base segments of a predetermlned width when they press the monofilaments 36 l~ZZ786 into the strips 26 so that the base segments are embedded in and bonded to the strips 26.
The striker bars 39 are controlled to alternately strike the platen 31 sothat the monofilaments 36 will be 5 bonded first to one and then to the other of the strips 26 wlth the lengths of monofllament 36 therebetween extending gene~ally normal totheir opposing surfaces to form a lamin-ated structure 43. The operational frequency of the striker bars 39 and/or the speed of the take-off device 33 are regulated to provide a desired spacing between the U-shaped lengths of monofilaments bonded to the strips 26. After the lamlnated structure 43 has passed through the ta~e-off device 33 so that the polymeric strips 26 have again solidi-fied, the laminated structure 43 engages a sharp trans~
15 versely positioned blade 44 which is parallel to and midway between the opposing surfaces of the strips 26 in the structure 43. The blade 44 ls reciprocated, as by a saber saw drive mechanism 45, to cut the laminated structure 43 into two brush-like halves 46, each of which halves 46 20 comprises one of the strips 26 and a multiplicity of gen-erally U-shaped lengths of the monofilaments 36 having pro~ectlng end portions. Each half 46 ls then guided along a separate path past a heated platen 47 which heats the air at the ends of the pro~ecting end portions of the mono-25 fllaments 36 to cause those ends to soften and form intogenerally hemispherically shaped heads. From the platens 47 the headed halves 46 are guided to devices which wind them on reels 49 ready to be cut to length for use as parts 11 for fasteners 10.

llZZ786 As will be understood, many modiflcations may be made in the method illustrated in Figure 6 without departlng from the spirit of the present invention. For example, the strips 26 of polymeric material may be formed by extruder heads positioned ad~acent the arcuate guides 31. The mono-filaments may be adhered in surface layers deposited on the strips 26 by adhesive applying devices between the roller and guides 31, and the guides need not be heated unless heat ls required to cure the adhesive. Also the knife 44 may be replaced with a hot wire for providing the cutting step, which hot wire may provide at least a portion of the heat requlred ~or heading.
Figures 7, 8, 9 and 10 illustrate alternate embodiments of parts of a fastener made from strip material according to the present invention, in which structures slmllar to structures ln the part 11 are similarly numbered except for the respectlve addltlon of one of the suff~xes "a", "b", "c" or "d".
The part 50 of a fastener lllustrated in Figure 7 can be made according to the method illu~trated in Figure 6 after a modlfication to the striker bars 39 which press the monofilaments 36 agaln~t the strlps 26 so that the end surfaces 42 of the strlking bars are set at an acute angle with the edges of the path for the strips 26. Like the part 10, the part 50 comprises an elongate backing 12a having parallel edges 19a. In the backing 12a are bonded a multi-pllclty of flexible resilient generally U-shaped monofila-ments 13a of longitudinally oriented polymeric material.
~ach monofllament 13a lncludes a central bight portion 17a, Z78~

and two pro~ecting stem portions 14a each termlnating in a head 18a defining an outer cam surface 20a. Also like the part 11, the bight portlons 17a of the U-shaped monofila-ment 13a are disposed generally parallel to each other and to the edges l9a, and a plurality of' groups of the bight portions 17a are disposed generally side by side to form a plurality of generally parallel straight rows of monofila-ments 13a and heads 18a. In the part 50 of Figure 7, however, the rows of monofilaments 13a are disposed at an acute angle with the parallel edges l9a of the part 50 which angle corresponds to the angle at which the striking bars are set.
Figures 8, 9 and 10 illustrate second, third and fourth alternate embodiments for the parts 60, 70 and 80 of fasteners made from strip material according to the present invention which strip material can also be made by the method illustrated in Figure 6 with the additlon of one method step.
The added method step is that of varying the position of the guide 37 transversely of the path for the strip 26. Such varlation can for example be done by cam arrangements in a sinusoidal pattern toproduce fastener parts with heads dis-posed in rows arranged as illustrated in Figure 8, or in a saw tooth pattern to produce heads disposed in rows as lllustrated in Figure 9. Alternatively, as illustrated in Figure 10, such varlation can be in a random pattern. In any event it is desirable that the variation shift the stems 14b, 14c or 14d of successive rows of U-shaped monofilaments 13b, 13c or 13d by about one half the width of the spacing between the U-shaped monofilaments 13b, 13c or 13d in a ~ZZ786 direction normal to the edges l9b, l9c or l9d. This lnsures that there is no uninterrupted path between the stems 14b, 14c or 14d in a direction parallel to the edges l9b, l9c or l9d.
Like the parts 10 and 50, the parts 60, 70 and ~0 each comprise a backing 12b, 12c or 12d having parallel edges l9b, l9c or l9d. In a bondlng layer of the backing are bonded a multiplicity of flexible resilient generally U-shaped monofilaments 13b, 13c or 13d of longitudinally oriented polymeric materlal. Each monofilament 13b, 13c or 13d includes a central bight portion 17b, 17c or 17d, and two proJectin~ stem portions 14b, 14c or 14d each terminating in a héad 18b, 18c or 18d defining an outer cam surface 20b, 20c or 20d. Also, like the parts 11 and 50, the bight portions 17b, 17c or 17d of the U-shaped monofllaments 13b, 13c or 13d are disposed generally parallel to each other, and a plurality of groups of the bight portions 17b, 17c or 17d are disposed generally side by side to form a plurality of generally parallel straight rows of U-shaped monofilaments 13b, 13c or 13d and heads 18b, 18c or 18d disposed at generally a right angle with the parallel edges 19b, l9c or l9d. In each of the parts 60, 70 or 80 it will be noted that the U-shaped monofilaments 13b, 13c or 13d in succes-slve rows are not aligned in a dlrection parallel with the edges l9b, l9c or l9d which improves the shear strength of fasteners made from two of the parts 60, 70 or 80 should the rows of U-shaped monofilaments 13b, 13c or 13d be allgned durlng engagement.
Figure 11 lllustrates an alternate embodiment of llZZ786 a fastener 90 accordlng to the present inventlon ln which a part 92 (similar in all respects to the part 10 Or Figure 1 and havlng similar parts similarly numbered wlth :
the addltlon of the sufflx "e") is engaged with pro~ecting fiber loops 94 pro~ectlng from the woven backing 96 of a part 98 comprising a length of commercially available material such as that designated "Scotchmate" brand nylon woven loop No. SJ3401 available from Minnesota Mining and Manufacturlng Company, St. Paul, Minnesota. As illustrated the part 92 includes a plurality of U-shaped monofilaments 13e having bight portions 17e bonded in a non-fibrous polymeric bonding layer 15e of a backing 12e ~or the part 92.
The U-shaped monofilaments 13e also include stem portions 14e pro~ecting fromthe bonding layer 15e. The stem portlons 14e support heads 18e with outer cam surfaces 20e adapted to deflect the resilient fiber loops 94 of the part 98 upon engagement therebetween so that the loops 94 releasably catch on latching surfaces 20e of the heads 18e. As illus-trated, the headed U-shaped monofllaments 13e are positioned and spaced as were the U-shaped monorilaments 13 of the part 11. Such positioning and spaclng is not required to arford proper engagement between the headed stems 14e and loops 94, however. Any positlon of the U-shaped monofilaments is suitable so long as the number of monofilaments ls ~uitable 25 L long as the number of monofilaments ls sultabl~ to pro-vide a desired degree of engagement therebetween. The spacing schemes illustrated in Figures 7, 8, 9 and 10 are Or no advantage, slnce shear ls not a problem between the loops 94 of the part 98 and the headed stem portions 14 o~

llZZ786 the part 92.
Example The following ls a speciflc non-limltlng example of a part of the type shown in Figure~ 1 through 5 produced by the method described wlth reference to Figure 6~ and test results relatlng to that part.
The part was made from 0.38 mlllimeter (0.015 inch) diameter polypropylene monofilament applied to a 25.4 mllllme~er (1 inch) wlde backing comprlslng a poly-propylene surface layer havlng a thlckness of about 0.76millimeter (0.030 inch). Flfteen of the monofilaments were applled over the central 19 milllmeter (3/4 inch) of the strip wldth to provlde a spacing Or about 1.3 millimeter (0.05 inch) center to center between the stems along the rows of U-shaped filaments. Each U-shaped fllament was formed to have a center to center width between lts pro-~ectlng stems of about 1.3 mllllmeter (0.05 lnch), and the ad~acent stems of ad~acent U-shaped monofllaments in a directlon normal to the rows of U-shaped fllaments were spaced at about 1.4 mllllmeter (o.o56 inch). The heml-spherlcal heads Or the monofllaments were in the range of about 0.9 to 1.0 mllllmeter (0.035 to 0.040 lnch) ln dlameter and the stems had a length of about 2.3 to 2.8 millimeters (0.030 to 0.110 inch) between the surface layer and the heads.
Two such parts were firmly adhered to a rlgid planar member on a testing devlce that would simultaneously engage and dlsengage the heads ln repetltive cycles. It was found that 1000 engagement-dlsengagement cycles reduced the force required to disengage the heads from 12.3 to 7.75 kllograms (27.3 to 17.1 pounds), and the force to engage the heads from 14.1 - 10.7 kilograms (31 to 23.6 pounds).
Also after the cycling force required to separate the engaged parts by sliding them relatlve to each other in the planes of thelr backing strlps was still about 14 kilo-grams (31 pounds) when the rows of U-shaped monofilaments were disposed at 90 degrees to each other, and between about 5 kilograms (12 pounds) when the rows of U-shaped monofila-ments were disposed parallel to each other. After the testing it was noted that none of the U-shaped monofilaments had pulled free of the backing.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for forming a strip material adapted to be cut into lengths that provide parts of fasteners, wherein said method comprises the steps of moving two non-fibrous polymeric strips from generally opposite directions around parallel arcuate spaced guides and away from the guides in the same direction along parallel paths; heating the polymeric strips on the spaced guides to soften them; feeding flexible, resilient polymeric monofilaments between the spaced guides from the sides thereof opposite said parallel paths and in a direction generally parallel to said parallel paths; alternately deforming the monofilaments into a first line of U-shaped portions while pressing the first line of U-shaped portions into engagement with one of the strips and then deforming the monofilaments into another line of U-shaped portions while pressing the other line of U-shaped portions into engagement with the other strip to embed and bond the U-shaped portions of the monofilaments in the strips in the positions that they are pressed into engagement therewith so that lengths of the mono-filaments between the U-shaped portions extend generally normally between the strips as the strips move along the parallel paths;
severing the monofilaments midway between the strips to form two brush-like halves; and heating the newly severed terminal ends of the monofilaments projecting from the strips to form heads having generally hemispherical surfaces opposite the strips.

2. A method according to claim 1 wherein said feeding step includes the step of varying the positions of said monofilaments transversely of said parallel paths.

3. An elongate strip material which may be severed into at least two lengths to form a fastener, comprising a backing com-prising a uniform non-fibrous nonoriented polymeric bonding layer of a predetermined thickness and having an exposed major surface;
and a multiplicity of flexible resilient monofilament portions deformed into U-shaped elements of longitudinally oriented polymeric material of a diameter less than said predetermined thickness, each U-shaped element including a central bight portion embedded in, bonded in and held only by said bonding layer, each U-shaped element also including two straight stem portions of essentially the same length extending in the same direction from the opposite ends of said bight portion, projecting generally normal to said exposed major surface of the surface bonding layer and having unsupported ends opposite said bight portion, each U-shaped element also including an enlarged generally hemispherical head at each unsupported end, each of the heads being generally concentric with its supporting stem portion, having a cam surface opposite its supporting stem portion adapted for engagement with the cam surfaces of heads along a different portion of the strip material to produce deflection of the stem and movement of the heads on the stems past each other upon movement of the heads toward each other with the portions of the backing behind the heads generally parallel, and having a surface opposite said cam surface which is generally planar and extends at generally a right angle from its supporting stem portion adapted to engage a similar surface on another head, the bight portions of said U-shaped elements being disposed generally parallel with a plurality of groups of the bight portions each being disposed generally side by side to form a plurality of generally parallel rows of stem portions with said heads along and between the rows being spaced at distances which, as an average, are generally no greater than the diameter of the heads so that simultaneous movement of all the heads of different portions of the strip material past each other can occur only upon resilient separation of many of said heads, with said stems being spaced apart a distance which, as an average, is at least as large as the diameter of said heads to afford positioning of the heads of one portion of the strip material between the stems of another portion of the strip material and with the length of each stem portion from the major surface to the head on its unsupported end being at least equal to the diameter of the head to afford deflection of the stems to allow simultaneous movement of all the heads of different portions of the strip material past each other at any relative angular orientation between the rows of stems of the portions.

4. A strip material according to claim 3 wherein said bonding layer comprises the same polymeric material as said mono-filaments and the bight portions of said U-shaped elements are fused in said bonding layer.

5. A strip material according to claim 3 wherein the sur-faces of said bight portions opposite said heads are about aligned with the surface of said bonding layer opposite said major surface.

6. A strip material according to claim 3 wherein the rows of U-shaped elements are straight and are disposed to form an acute angle with the longitudinal edges of said strip material.

7. A strip material according to claim 3 wherein said back-ing further comprises a layer of adhesive on the surface of said bonding layer opposite said major surface.

8. A strip material according to claim 3 wherein the length of each stem portion from said major surface to the head on its unsupported end is in the range of 2-1/4 to 3 times the diameter of the head.

9. A strip material according to claim 3 wherein the U-shaped elements in successive rows are out of alignment in a direction parallel to the bight portions of said monofilaments.

10. A strip material according to claim 3 wherein the heads on each U-shaped elements are more closely spaced than are ad-jacent heads between adjacent rows of U-shaped elements.