US3077017A

US3077017A - Apparatus and method for producing nonwoven fabrics

Info

Publication number: US3077017A
Application number: US748236A
Authority: US
Inventors: Harmon Carlyle
Original assignee: Chicopee Manufacturing Corp
Current assignee: Chicopee Manufacturing Corp
Priority date: 1958-07-14
Filing date: 1958-07-14
Publication date: 1963-02-12
Anticipated expiration: 1980-02-12

Description

Feb. 12, 1963 c. HARMON 3,077,017

A APPARATUS AND METHOD FOR PRODUCING NONWOVEN FABRICS Filed July 14, 1958 6 Sheets-Sheet l C. HARMON Feb. 12, 1963 APPARATUS AND METHOD FOR PRODUCING NONWOVEN FABRICS Filed July 14, 1958 6 Sheets-Sheet 2 Feb. 12, 1963 c. HARMON 3,077,017

APPARATUS AND METHOD FOR PRODUCING NONWOVEN FABRICS Filed July 14, 1958 6 Sheets-Sheet 3 Feb. 12, 1963 C. HARMON APPARATUS AND METHOD FOR PRODUCING NONWOVEN FABRICS Filed July 14, 1958 6 Sheets-Sheet 4 I I w u .Bwwvur Feb. 12, 1963 c. HARMON 3,077,017

APPARATUS AND METHOD FOR PRODUCING NONWOVEN FABRICS Filed July 14, 1958 6 Sheets-Sheet 5 M N D 0 .HH H 558 3 5 HE P F I om b 5 oon BE 59 Lujadw," f/cuvnmy & w

M252: mZEruu 524 w w zoEwoa #265623 R H E E E P am: Hm H o Feb. 12, 1963 c. HARMON 3,077,017

APPARATUS AND METHOD FOR PRODUCING NONWOVEN FABRICS Filed July 14, 1958 e Sheets-Sheet e (\1 \1 z m D M a 3 B m "9 m U A? b g M o P "7 U gafs J/wrmcn;

United States Patent 5,077,017 APPARATUS AND METRO?) FOR ERODUCING N ONWOVEN FABRIQS Carlyle Harmon, Scotch Plains, N.J., assignor to 'Chicopee Manufacturing Corporation, a corporation of Massachusetts I Filed July 14, B58, Ser. No. 748,236 15 Claims. (Cl. 28----].)

This invention relates to an apparatus and method for producing nonwoven'fabrics directly from fibers without the use of conventional spinning, weaving, or knitting operations.

PRODUCTS OF PRIOR ART Heretofore, nonwoven fabrics have been essentially diifere-nt in structure from fabrics which have been woven or knitted. In a woven or knitted fabric, the fibers .of the material making up the. fabric do not occur individually, but are twisted into yarns or threads which in turn are woven or knitted into the fabric. In the well known spinning operation, fibers are spun or twisted together tightly into frictional and interlocking engagement with one another to form yarns which are substantially circular in cross section. It is these yarns, not the fibers acting individually, which serve as the structural members of the resulting woven or knitted fabrics. Generally speaking, these fabrics comprise reticular structures of intersecting, intertwining yarns which define interstices between them.

Nonwoven fabrics have been of two main types, felts and bonded webs. In each of these, the fibers making up the fabric occur individually and act individually as structural members.

This is true even though the fibers in many felts are so highly interlocked and compressed together that it is difficult to identify individual fibers. Hat felts, for instance, are extremely dense, relatively hard fabrics without apparent interstices, which are quite dissimilar in appearance and qualities to woven or knitted structures.

In contrast, the fibers in bonded webs are usually fiatly assembled in layers, Whether more or less oriented in one direction as in a card Web or arranged in a random manner as in an air laid isotropic web. Various bonding agents have been used to print a binder pattern on such webs or to impregnate them to hold the individual fibers together. In this type of fabric, the fibers may remain relatively straight and overlapping one another with very little interlocking between them. They are usually arranged in a more or less uniformly spaced condition in the plane of the web, in such a way that only very small randomly occurring interstices are apparent between the overlapped fibers and those fibers between interstices remain spaced and more or lessfla-tly arranged, possessing little similarity to the yarns of woven or knitted fabrics.

FABRIC PRODUCED BY PRESENT INVENTION The present invention contemplates a nonwoven fabric wherein the fibers are arranged to define a predetermined pattern of holes or openings with most of the fiber segments bordering the holes extending in substantial parallelism with portions of the perimeters of the holes. In general, the fibers are arranged in interconnected groupings or web areas extending between the holes in a predetermined pattern corresponding to the aforementioned pattern of holes. The resulting fabric may if desired be made to resemble a particular woven or knitted fabric.

The fiber groupings or groups just mentioned are connected by fibers extending from one to another in such away that they are common to a plurality of groupings.

3,077,017 Fatented Feb. 12, 1963 It is preferred that the aver-age length of the fibers be considerably greater than the lengths of the groups containing them with the'result that the groups predominately comprise only parts or segments of the fibers passing through them. Preferably the fibers average at least about inch in length and are textile-like in nature, i.e.,fiexible and distinct or unbeaten in the case of Wood pulp. In general, the groupings are connected at junctures wherein the fibers extend in a plurality of diverse directions, While the fiber segments in the groups are relatively parallelized with respect to one another and more closely assembled than at the junctures.

Due to their structure and appearance and other qualities, fabrics produced by the method and apparatus of this invention are particularly adapted for use in surgical dressings, absorbent dressings such as sanitary napkins and diapers, most suitably for covering sanitary napkins and diapers, in wiping cloths, toweling, filter materials, lining materials, industrial base fabrics, as a substitute for gauze-like fabrics in general, and a variety of other applications.

SUMMARY OF PRESENT INVENTION The present invention contemplates a method and 'an apparatus for producing the fabric of this invention from a layer of irregularly arranged, overlapping fibers. The layer may be a nonwoven web of fibers, for example, fibers of rayon or cotton. The individual fibrous elements of the layer are capable of movement under the influence of applied rearranging forces. In general, the starting materials in the method of this invention may be any of the starting materials described in the Kalwaites application SN. 567,275, fiied February 23, 1956 and now US. Patent No. 2,862,251. The preferred starting material is an unbonded fibrous web.

In the first step of the method of this invention, a starting layer of irregularly arranged, overlapping fibers in frictional engagement, the individual fibers of which are capable of movement under applied rearranging forces, is positioned between a backing member and a group of prongs arranged in positions corresponding to the foraminous portions of the predetermined pattern for the fabric to be produced, and the prongs and backing member are moved together to cause the prongs to penetrate the fibrous layer and move segments of the fibers from the local spaces in the layer which are occupied by the ad vancing prongs, and into closer proximity and increased parallelism with segments of other fibers surrounding those spaces. The prongs employed are preferably sharp, tapered implements such as needles.

The lateral translatory forces applied to the layer of fibers when the prongs penetrate the layer act to push segments of some of the fibers into the spaces between the prongs. As the prongs continue their penetration of the fibrous layer, they rub against the immediately adjacent fibers and produce a vibratory effect in these and other fibers. The vibration of a given fiber may act to free the fiber to an extent from its overlapping and frictional engagement with other fibers in the layer, so that as it is moved laterally it may also slide along its longitudinal axis.

In the second step of the method of this: invention, the fibers that have been pushed aside by the advancingprongs are pressed against the backing member while the prongs are still in their advanced position. This pressure on the fibers completes the rearrangement of the fibers of the starting layer to produce the final rearranged nonwoven fabric. The pressing force accomplishes this by causing many of the fibers vto slide along their respective longitudinal axes and into positions of mechanical equilibrinrn. The fibrous layer, even though light in weight,

will nevertheless have an appreciable thickness because of the structure of the web or other material. When the layer is pressed against the backing member, this compresses the fiber structure in thickness and indoing so shakes'the structure up somewhat. Since slight pressures may, in cooperation with the lateral rearranging forces exerted by the prongs, be suflicient to loosen the overlapping and frictional engagement with other fibers, the pressure against the fiber structure will help to slide individual fibers along their longitudinal axes and into new positions of mechanical equilibrium with other fibers, in which positions they remain and are restrained by frictional forces from returning to the positions they originally occupied before being displaced by the advancing prongs.

In the third step of the method of this invention the prongs are withdrawn from the fibrous layer, while the pressing force holding the rearranged fibers against the backing member is maintained. Continuance of the pressing force during withdrawal of the prongs avoids any disarrangement of the fibers which might be caused by the rubbing of the withdrawing prongs against them.

In the preferred form of the method of this invention, the starting fibrous layer is wet out before the layer is subjected to the three steps just described. The wetting of the fibers of the starting layer causes them to be more easily rearranged by the forces applied during the first two steps of the method.

The apparatus by means of which the above described method is practiced will be fully described in the following specification, taken in conjunction with the accompanying drawings, showing a preferred illustrative embodiment of the apparatus, and also diagrammatically showing the structural relationships between component parts of the apparatus at specified stages of the method. In the drawmgs:

FIG. 1 is an end elevational view of one embodiment of the apparatus of this invention, looking at the discharge end of the machine;

FIG. 2 is a side elevational view of the apparatus, looking from the left hand side of the drawing of FIG. 1;

FIG. 3 is a plan view of the apparatus;

FIG. 4 is a diagrammatic view showing the position of the eccentric for controlling the vertical movement of the prongs, relative to the drive shaft, at the time the prongs are in their uppermost position;

FIG. 5 is a diagrammatic view showing the position of the eccentric for controlling the vertical movement of the clamping or pressure plate, relative to the drive shaft, at the time the prongs are in their uppermost position;

FIG. 6 is a diagrammatic view, similar to FIG. 4, showing the eccentric of FIG. 4 when the prongs have been moved downwardly through half their total movement;

FIG. 7 is a diagrammatic view, similar to FIG. 5, showing the eccentric of FIG. 5 when the prongs are in the position indicated in FIG. 6;

FIG. 8 is a diagrammatic view, similar to FIG. 4, showing the eccentric of FIG. 4 when the prongs are in their lowermost position;

FIG. 9 is a diagrammatic view, similar to FIG. 5, showing the eccentric of FIG. 5 when the prongs are in their lowermost position;

FIG. 10 is a functional graph showing the vertical positions of the prongs and the clamping or pressure plate, relative to the fibrous starting layer, through one revolution of the drive shaft;

FIG. 11 is a graph showing the longitudinal travel of the fibrous starting layer during one revolution of the drive shaft, the longitudinal travel of the fibrous layer being indicated by the vertical ordinate of the graph; and

FIG. 12 is a diagrammatic view showing the vertical positions of the prongs and the clamping or pressure plate relative to the fibrous starting layer and supporting felt at various angular positions of the drive shaft.

Frame Referring to FIGS. 1, 2 and 3 of the drawings, the frame of the machine comprises a pair of vertically disposed I beams 2 and 3 at the feed end of the machine and a pair of similar I beams 4 and 5 at the discharge end of the machine. A longitudinally disposed I beam 6 is secured at one end to beam 2 by means of brackets 7 and 8, and at its other end to beam 4 by means of brackets 9 and 10. A second longitudinally disposed I beam 11 is secured at its ends to intermediate portions of

beams

2 and 4. At the opposite side of the machine, beams 3 and 5 are rigidly connected to each other in a similar manner by I beams 12 and 13.

Beams

6 and 12 are tied together adjacent the central portions thereof by transversely extending channel mem-- bers 14 and 15.

Channels

14 and 15 face in opposite directions and are spaced apart for a reason hereinafter disclosed.

Rolls Beams

2 and 3 cooperate to support a pair of vertically spaced parallel

rotatable shafts

16 and 17 on which a spring pressed feed roll 18 and a wet out roll 19 are respectively mounted.

Beams

4 and 5 cooperate to support a pair of

rotatable shafts

20 and 21, similar in vertical position to

shafts

16 and 17, on which discharge rolls 22 cifically described.

Housings

24, 25, 26 and 27 are mounted on the top of

beams

2, 3, 4 and 5, respectively, for enclosing the spring mechanism (not shown) for applying pressure to both ends of

shafts

16 and 20, respectively. A pan 28 is mounted below wet out roll 19 to hold water in which roll 19 is partially immersed. If desired, a water soluble adhesive binder may be included in the water in order to apply the binder to the fibrous starting layer as it passes between

rolls

18 and 19.

Cam-Bearing Drive Shaft A plurality of bearings 29 are mounted between

channel members

14 and 15 in longitudinally spaced relationship. The perimeter of the bearings is square or rectangular, to provide a maximum of support between the channel members. Each bearing has a vertically disposed cylindrical bore 30 extending entirely through the bearing for a purpose hereinafter described.

' A bearing support 31 is bolted to the upper. edge of beam 6, as indicated at 32; a similar bearing support 33 is bolted to the upper edge of beam 12, as indicated at 34. .These bearing supports are provided with horizontally aligned bearings which rotatably support the opposite ends of drive shaft 35. The drive shaft extends transversely of the machine above cylindrical bores 30 and in vertical alignment therewith.

Bearings

36 and 37 provide intermediate support for drive shaft 35. Bearing 36 is mounted in a bearing support 38 bolted to the upper edges of

channel members

14 and 15, as indicated at 39. Bearing 37 is mounted in a bearing support 40 bolted to the upper edges of

channel members

14 and 15, as indicated at 41.

Drive shaft 35 is rotated by an endless chain 42 extending around a sprocket 43 mounted on shaft 35 and a sprocket 44 mounted on a shaft 45. Shaft 45 is rotatably mounted in bearings carried by

beams

11 and 13. The end of shaft 45 opposite sprocket 44 has a sprocket 46 H mounted thereon. An endless chain 47 extends around sprocket 46 and a sprocket 48 mounted on the output shaft 49 of a motor 50 in order to drive shaft 45. Motor 50 is mounted on a bracket 51 secured to

beams

2 and 11. I

Two series of cams 51 and 52 (FIGS. 2 and 4-9) are shaft 35.

rigidly mounted on drive shaft 35 in longitudinally spaced relationship. As shown in FIGS. 4 to 9, inclusive, cams 51 are positioned in this embodiment approximately 36 behind cams 52 in their angular relationship to drive In other words, drive shaft 35 must be rotated approximately 36 from its angular position in which cam 52 is in its top center position, for example, before cam 51 reaches its top center position. Each cam 51 is rotatably mounted in a bearing 53 fixed on the inner surface of a ring 54 comprising the upper end of an eccentric 55. Each cam 52 is similarly mounted in a hearing 56 on the inner surface of a ring 57 comprising the upper end of an eccentric 58.

Prong-Carrying Plate The lower end of each eccentric 55 is pivotally connected to the upper end of a rod 59, as indicated at 64 Each rod 59 has a fiat plate 61 on its lower end. Plate 61 may be integral with rod 59, or may be rigidly secured thereto in any suitable manner as by welding. Each rod 59 is slidably mounted in a bearing 2& and is reciprocated vertically in said hearing as each eccentric 55 is moved by the rotation of drive shaft 35 and its respective cam 51.

Plates 61 cooperate to support a fiat prong-carrying plate 62 secured to their bottom surfaces, preferably by welding. As shown in FIG. 1, plate 62 has a plurality of prongs 63 depending from its lower surface. The prongs are preferably sharp, tapered implements, such as needles, and are grouped in any desired predetermined relationship to correspond to the pattern of the nonwoven fabric to be produced.

Clamping Plate The lower end of each eccentric 58 is pivotally connected to the upper end of a rod 64, as indicated at 65. Arm 66 extending laterally in opposite directions from the lower end of each rod 64 has a vertically extending cylindrical sleeve 67 at each end. A pressure or clamping plate 63 of somewhat larger area than prong-carrying plate 62 is positioned below arms 66 in parallel relationship thereto.

Pins 69 extend upwardly from plate 68 through the sleeves 67 of each arm 66. Pins 69 are secured to plate 68 in any suitable manner. A coiled compression spring 76 encircling each pin 69 is baised between the lower edge of sleeve 67 and plate 68, and normally maintains the maximum permitted vertical spacing between arms 66 and plate 68. Plate 63 is provided with a plurality of vertical perforations 71 arranged in conformity with the arrangement of prongs 63 to permit those prongs to project therethrough.

Although the drawings show three eccentric rings 54 supporting plate 62 and two eccentric rings 57 supporting plate 68, it is obvious that the number of supports may be varied, if desired. Cams 51 are in horizontal alignment with each other so that rods 59 are moved as a unit to reciprocate plate 62 without possibility of binding. Cams 52 are similarly in horizontal alignment with each other, but as already explained above are out of phase by approximately 36 relative to cams 51. Accordingly, plate 63 is also reciprocated without possibility of binding. The timed relationship between the reciprocation of

plates

62 and 63 will be hereinafter discussed in connection with the operation of the machine.

Backing Member As shown in FIG. 2, a layer 72 of fibers is fed between spring pressed roll 18 and wet out roll 19 and on to a backing member 73 comprising an endless belt. Backing member 73 is preferably felt or loosely woven fabric that may be readily penetrated by prongs 63, and extends around rolls 74 and 75 disposed transversely of the apparatus adjacent opposite ends thereof.

Roll 7% is mounted on a shaft 76 supported by

beams

11 and 13 adjacent the feed end of the machine. Shaft 76 may be fixed in its supports or may be rotatably mounted in suitable bearings. If shaft 76 is fixed, roll 74 is rotatably mounted on the shaft. Roll 75 is keyed to a shaft 77 rotatably mounted in suitable bearings (not shown) that are supported by

beams

11 and 13 adjacent the discharge end of the machine.

The fibrous layer 72 to be rearranged in accordance with this invention is fed from the backing member 73 between discharge rolls 22 and 23 as a nonwoven fabric '78. Roll 22 is omitted from FIG. 1 for clarity.

Base Plate The portion of backing member 73 positioned directly below clamping or pressure plate 68 is supported by a base plate 7? extending below the upper reach of backing member 73 and having its ends mounted on

beams

11 and 13, as shown in FIGS. 1 and 2.

Base plate 79 is provided with vertical perforations 80 aligned vertically with perforations 71 in clamping plate 68.

Drive Mechanism A crank arm 81 keyed to shaft 45 is pivotally connected at its other end to one end of a link 82, as indicated at 63. The opposite end of link 82 is pivotally connected to one end of an arm 84, as indicated at 85. The other end of arm 84 is loosely mounted on shaft 77. The rotation of crank arm 81 with shaft 4-5, which is rotated continuously by motor 50, swings arm 84 back and forth through a predetermined are because of the pivotal connections of link 82.

A ratchet 86 and a sprocket 87 are keyed to shaft 77. A pivoted, spring pressed pawl 88, mounted on arm 84, engages teeth 89 of ratchet $6 to rotate shaft 77 in one direction when arm 34 is swung in the clockwise direction as seen in FIG. 2. When arm 84 is: swung in the opposite direction, i.e., counterclockwise as seen in FIG. 2, pawl 38 rides over teeth 89 and does not move shaft 77. An endless chain 90 extends around sprocket 87 and a sprocket 91 keyed to shaft 21, to rotate shaft 21 and discharge roll 23 when shaft 77 is rotated.

Drying means 92 of any conventional type is shown diagrammatically at the right-hand side of FIG. 2, where it will operate to dry the rearranged fabric discharged from

rolls

22 and 23.

OPERATION OF APPARATUS The operation of the apparatus disclosed thus far in this specification will now be described.

Longitudinal Movement of Fibrous Layer A layer 72 of fibers is fed between

rolls

18 and 19 from any suitable source. The fibers, preferably irregularly arranged, overlapping fibers, are positioned on backin" member 73. The layer or web is then extended to pass between discharge rolls 22 and 23, which pull the fibrous web through the apparatus during the normal operation thereof. The rotation of roll 23 "is intermittent, and is synchronized with the vertical movements of prongs 63 and clamping or pressure plate 68.

Shaft 45, which is rotated continuous y during the operation of the machine, rotates drive shaft 35 continuously through chain 42, and rotates shaft 21 intermittently through crank arm 81, link 8-2, arm 84, shaft 77, sprocket 87, and chain 94 In FIG. 2, prongs 63 are shown in their uppermost position, and arm 84-, in its solid line position, is moving clockwise. in this position pawl 88 engages teeth 89 to rotate ratchet 86 clockwise. The rotation of shaft 77, to which ratchet S6 is keyed, causes chain 9%) to rotate roll 23, thus pulling the fibrous web longitudinally of the machine.

Accompanying Vertical Movement of Prongs and Clamping Plate FIG. 10 gives a diagrammatic showing of successive angular positions of drive shaft 35, numbered from I through IX, and the corresponding vertical movement of the prongs and clamping plate that accompanies the longitudinal movement of fibrous layer 72.

I a The dark solid line in FIG. indicates the sine curve representing the vertical movement of the prongs or needles relative to the rotation of drive shaft 35, and the broken line indicates the sine curve representing the vertical movement of the clamping plate. The horizontal line N indicating the center of the sine curve of the prongs is located a short distance above the upper surface of the fibrous web. The prongs start penetrating the fibrous web shortly after the drive shaft has rotated 180 from the zero reference position shown in FIG. 10, and move out of engagement with the web shortly before the drive shaft completes one revolution. The horizontal line C indicating the center of the sine curve of the clamping plate is located above line N. The clamping plate engages the fibrous web for only about one fourth of the revolution of the drive shaft.

The FIG. 2 position of the various elements is shown graphically at drive shaft position II in FIGS. 10, 11 and 12. Reference to position II in FIGS. 10 and 12 shows that the prongs or needles are in their uppermost position, and that the clamping plate is above the particular web increment which forms the basis of reference in the diagrams of FIGS. 10, 11 and 12. In FIG. 11, the ascending curve of the line representing the longitudinal position of the web increment as said line crosses the 90 marker shows that the fibrous layer is moving longitudinally of the machine.

After crank arm 81 has moved counterclockwise 90 from the position shown in FIG. 2, arm 84 will be in its extreme left position.- Further rotational movement of the crank arm will swing arm 84 toward the right, thereby disengaging pawl 88 from teeth 89 and stopping the longitudinal movement of the fibrous web through the machine.

This is shown in drive shaft position III of FIG. 11 by the levelling of the line representing the longitudinal position of an increment of the fibrous web.

Penetration by Prongs and Subsequent Clamping FIG. 10 shows that the prongs and clamping plate both start their downward movement before the web incre- ,is possible because of base plate 79, except for the compressibility of the fibrous layer and felt backing member 73. I

. At drive shaft position VII the fibrous layer and backing member have been compressed as far as possible, and the clamping plate remains stationary for an interval represented by the horizontal portion of the broken line indicating the vertical position of the clamping plate. The downward movement of the rods 64 .and arms 66 continues during this interval and is absorbed by springs 70, The resistance of compressed fibrous web 72, backing member 73 and base plate 79 is greater than the resistance of springs 70, and the springs remain compressed until cams 52 start to move clamping plate 68 upwardly just before drive shaft position IX is reached.

The prongs are lifted out of engagement with the rearranged fibrous web between drive shaft positions VIII and IX, and the clamping plate is lifted from the fibrous web just before drive shaft 35 completes its full revolution. Immediately thereafter arm 84 starts swinging to the left, and the longitudinal movement of the fibrous web is resumed.

8 Rearrangement of Fibrous Layer As the prongs move downwardly through the fibrous web, they exert lateral force against the fibers to reposition at least some of them. The prongs move segments of the fibers from the local spaces in the web which are occupied by the descending prongs and into closer proximity and increased parallelism with segments of other fibers surrounding those spaces.

Synchronization of Various Actions The synchronization of the intermittent longitudinal move-ment of the fibrous web and the vertical movements of the prongs and clamping plate, whereby the fibrous Web is held against longitudinal movement while it is engaged by either the prongs or the clamping plate, is eifected by proper positioning of arm 84 relative to the positions of

eccentrics

55 and 58.

Arm 84 is located at one limit of its swinging movement when link 82 and crank arm 81 are. in the extended straight line position indicated by dotted lines in FIG. 2. Arm 84 moves clockwise until crank arm 81 has been rotated through 180, at which point the other extreme position of arm 84 is reached. The ratchet and pawl relationship causes the fibrous web to move longitudinally of the machine during the clockwise movement 'of arm 84, and to remain stationary during its counter- 40 clockwise movement.

FIG. 10 shows that the drive shaft must rotate through slightly more than from the position of extreme lift of the prongs before the prongs start to penetrate the fibrous web. 'When eccentric 55 is in its uppermost position as shown in FIG. 2, arm 84 is located half-way between its two extreme positions. When crank arm 81 is rotated 90 from this intermediate position it stops the longitudinal movement of the fibrous web, by disengaging pawl 88 from the teeth of ratchet 86, just before the prongs engage the fibrous web.

Crank arm 81 must be rotated another to complete one revolution before pawl 88 is engaged with the teeth of ratchet 86 to start longitudinal movement of the fibrous web once again. FIG. 10 shows that clamping plate 68 moves upwardly out of engagement with the fibrous web shortly before the drive shaft completes its revolution. Therefore the clamping plate and the prongs are out of engagement with the fibrous web during each intermittent longitudinal movement of the fibrous web.

The above-detailed description of this invention has been given for clearness of understanding. No unnecessary limitations shall be understood therefrom, as modifications will be obvious to those skilled in the art.

I claim:

1. Apparatus for producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: a backing member; a group of prongs arranged in locations corresponding to said pattern of holes, said group of prongs having a withdrawn position spaced from said backing member and an extended position in which said prongs extend beyond the surface of the backing member; actuating means for selectively bringing said prongs and backing member together with said fibrous layer in the space therebetween, so as to cause the prongs to move into their extended positions and penetrate said layer to push segments of some of said fibers laterally in the layer, and for selectively moving them apart; and means for initially pressing the fibers of said layer against said backing member after said prongs have penetrated said layer and for continuing said pressure while the prongs are being withdrawn from the layer and until after their withdrawal is completed, whereby the fibers are moved not only laterally but also along their respective center lines, with respect to other fibers in said layer, so as to permit the rearranged fiber segments to remain in mechanical equilibrium in their new positions.

2. Apparatus for producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: means for wetting out said fibrous layer; a backing member; a group of prongs arranged in locations corresponding to said pattern of holes, said group of prongs having a withdrawn position spaced from said backing member and an extended position in which said prongs extend beyond the surface of the backing member; actuating means for se lectively bringing said prongs and backing member together with said wet fibrous layer in the space therebetween, so as to cause the prongs to move into their extended positions and penetrate said layer to move segments of some of said fibers laterally in the layer, and for selectively moving them apart; means for initially pressing the fibers of said layer against said backing member after said prongs have penetrated said layer and for continuing said pressure while the prongs are being withdrawn from the layer, whereby the fibers are moved not only laterally but also along their respective center lines, with respect to other fibers in said layer, so as to permit the rearranged fiber segments to remain in mechanical equilibrium in their new positions; and means for drying said rearranged fiber segments to produce a foraminous fabric.

3. Apparatus for producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregulariy arranged, overlapping fibers which comprises: means for wetting out and for applying adhesive binder to said fibrous layer; a backing member; a group of prongs arranged in locations corresponding to said pattern of holes, said group of prongs having a Withdrawn position spaced from said backing member and an extended position in which said prongs extend beyond the surface of the backing member; actuating means for selectively bringing said prongs and backing member together with said wet fibrous layer in the space therebetween, so as to cause the prongs to move into their extended positions and penetrate said layer to move segments of some of said fibers laterally in the layer, and for selectively moving them apart; means for initially pressing the fibers of said layer against said backing member after said prongs have penetrated said layer and for continuing said pressure while the prongs are being withdrawn for the layer, whereby the fibers are moved not only laterally but also along their respective center lines, with respect to other fibers in said layer, so as to permit the rearranged fiber segments to remain in mechanical equilibrium in their new positions; and means for drying said rearranged fiber segments to produce a foraminous fabric.

4. A machine for forming a nonwoven fabric having a predetermined pattern from a layer of irregularly arranged fibers, said machine comprising an apertured base plate, an apertured pressure plate positioned above said apertured base plate in spaced relationship, a plurality of needles projecting downwardly through the apertures of said pressure plate in vertical alignment with the apertures of said base plate, means for positioning a layer of irregularly arranged fibers between said base plate and said pressure plate, actuating means for selectively moving said needles downwardly to perforate said layer of irregularly arranged fibers and to move individual fibers relative to the other fibers of said layer to position them between adjacent needles, and for selectively moving said needles upwardly as soon as said clamping means to be hereinafter described becomes effective, clamping means operable only after said needles have been moved downwardly to perforate said layer of fibers for holding said pressure plate against said fibers to compress them, and control means for causing said clamping means to hold said pressure plate against said fibers until after said needles have been withdrawn from the fibers.

5. A machine for forming a nonwoven fabric having a predetermined pattern from a layer of irregularly arranged fibers, said machine comprising an apertured base plate, an apertured pressure plate positioned above said apertured base plate in spaced relationship, a plurality of needles projecting downwardly through the apertures of said pressure plate in vertical alignment with the apertures of said base plate, means for intermittently moving a layer of irregularly arranged fibers between said base plate and said pressure plate, each step of said intermittent motion having a length approximately equal to the dimension of said pressure plate in the direction of movement of said layer of fibers, actuating means for selectively moving the needles downwardly during the interval between successive steps to perforate said layer of fibers and to move individual fibers relative to the other fibers in said layer to position them between adjacent needles, and for selectively moving said needles out of engagement with said fibers while the fibers are under compression as hereinafter described, means operable only after said needles have been moved downwardly to perforate said layer of fibers for holding said pressure plate against said fibers to compress them.

6. A machine for forming a nonwoven fabric having a predetermined pattern from a layer of irregularly arranged fibers, said machine comprising an apertured base plate, an apertured pressure plate positioned above said apertured base plate in spaced relationship, a plurality of needles projecting downwardly through the apertures of said pressure plate in vertical alignment with the apertures of said base plate, a pair of rolls operable to position a layer of irregularly arranged fibers between said base plate and said pressure plate, means for actuating said rolls intermittently, actuating means synchronized with said roll actuating means for selectively moving said needles downwardly during the interval between successive movements of said layer of fibers to perforate said layer of fibers and to move individual fibers relative to the other fibers of said layer to position them between adjacent needles, and for selectively withdrawing said needles from said fibrous layer while said fibers are under compression as hereinafter described, and means operable only after said needles have been moved downwardly to perforate said layer of fibers for holding said pressure plate against said fibers to compress them during the interval between two successive actuations of said rolls in order to set the fabric formed by said fibers.

7. The method of producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: pushing se ments of fibers in said fibrous layer laterally from each local area of the layer corresponding to one of the holes in said predetermined pattern, into closer proximity and increased parallelism with segments of other fibers in positions surrounding said local area, by application of mechanical fiber rearranging forces having components parallel to said fibrous layer, said forces being applied first only at the center of said area and thereafter at points progressively nearer the perimeter of the area; after the distance of the points of application of said fiber rearranging forces from the centers of their respective local areas has reached a maximum, mechanically confining said rearranged fiber segments against lateral movement from their new positions back toward their original positions in the local areas from which they were pushed; pressing said fibrous layer between two complementary surfaces '50 that the rearranged fibers will not only have moved laterally but also will move along their respective center lines, with respect to other fibers in said layer, and the rearranged fiber segments will remain in mechanical equilibrium in their new positions; terminating said confinement of the rearranged fiber segments against movement back into the areas from which they were originally pushed; and releasing the pressure exerted by said two complementary surfaces upon the rearranged fibers comprising the resulting nonwoven fabric.

8. The method of producing a nonwoven fabric having 'a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: pushing segments of fibers in said fibrous layer laterally from each local area of the layer corresponding to one of the holes in said predetermined pattern, into closer proximity and increased parallelism with segments of other fibers in positions surrounding said local area, by application of mechanical fiber rearranging forces having components parallel to said fibrous layer, said forces being applied first only at the center of said area and thereafter at points progressively nearer the perimeter "of the area; after the distance of the points of application of said fiber rearranging forces from the centers of their respective local areas has reached a maximum, mechan- -ically confining said rearranged fiber segments against lateral movement from their new positions back toward their original positions in the local areas from which they were pushed; pressing said fibrous layer between two complementary surfaces for at least as long as said fiber segments are thus confined against movement back toward their original positions, so that the rearranged fibers will not only have moved laterally but also will move along their respective center lines, with respect to other fibers in said layer, and the rearranged fiber segments will remain in mechanical equilibrium in their new positions; terminating said confinement of the rearranged fiber segments against movement back into the areas from which they were originally pushed; and finally releasing the pressure exerted by said two complementary surfaces upon the rearranged fibers comprising the resulting nonwoven fabric.

9. The method of producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: wetting said fibrous layer; pushing segments of fibers in said wet fibrous layer laterally from each local area of the layer corresponding to one of the holes in said predetermined pattern, into closer proximity and increased parallelism with segments of other fibers in positions surround- ,ing said local area, by application of mechanical fiber rearranging forces having components parallel to said fibrous layer, said forces being applied first only at the center of said area and thereafter at points progressively nearer the perimeter of the area; after the distance of the points of application of said fiber rearranging forces from the centers of their respective local areas has reached a maximum, mechanically confining said rearranged fiber segments against lateral movement from their new positions back toward their original positions in the local areas from which they were pushed; pressing said fibrous -layer between two complementary surfaces so that the rearranged fibers will not only have moved laterally but also will move along their respective center lines, with respect to other fibers in said layer, and the rearranged fiber segments will remain in mechanical equilibrium in their new positions; terminating said confinement of the rearranged fiber segments against movement back into the areas from which they were originaly pushed; releasing the pressure exerted by said two complementary surfaces upon the rearranged fibers; and drying said rearranged fiber segments to produce a nonwoven fabric. 10. The method of producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: wetting and applying adhesive binder to said fibrous layer; pushing segments of fibers in said wet fibrous layer laterally from each local area of the layer corresponding to one of the holes in said predetermined pattern, into closer proximity and increased parallelism wtih segments of other fibers in positions surrounding said local area, by application of mechanical fiber rearranging forces having components parallel to said fibrous layer, said forces being applied first only at the center of said area and therafter at points progressively nearer the perimeter of the area; after the distance of the points of application of said fiber rearranging forces from the centers of their respective local areas has reached a maximum, mechanically confining said rearranged fiber segments against lateral movement from their new positions back toward their original positions in the local areas from which they were pushed; pressing said fibrous layer between two complementary surfaces so that the rearranged fibers will not only have moved laterally but also will move along their respective center lines, with respect to other fibers in said layer, and the rearranged fiber segments will remain in mechanical equilibrium in their new positions; terminating said confinement of the rearranged fiber seg ments against movement back into the areas from which they were originally pushed; releasing the pressure exerted by said two complementary surfaces upon the rearranged fibers; and drying asid rearranged fiber segments to produce a nonwoven fabric.

11. Apparatus for producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: a backing member; a group of prongs arranged in locations corresponding to said pattern of holes, said group of prongs having a withdrawn position spaced from said backing member and an extended position in which said prongs extend beyond the surface of the backing member; actuating means for selectively bringing said prongs and backing member together with said fibrous layer in the space therebetween, so as to cause the prongs to move into their extended positions and penetrate said 'layer to push segments of some of said fibers laterally in the layer, and for selectively moving them apart; means for initially pressing the fibers of said layer against said backing member after said prongs have penetrated said layer and for continuing said pressure while the prongs are being withdrawn from the layer and until after their withdrawal is completed, whereby the fibers are moved not only laterally but also along their respective center lines, with respect to other fibers in said layer, so as to permit the rearranged fiber segments to remain in mechanical equilibrium in their new positions; said actuating means including timing means for controlling the sequence of the penetrating, pressing and withdrawing actions of the respective means.

12. Apparatus for producing a nonwoven fabric having a predetermined pattern of holes from a layer or" irregularly arranged, overlapping fibers which comprises: a backing member; a group of prongs arranged in locations corresponding to said pattern of holes, said group of prongs having a withdrawn position spaced from said backing member and an extended position in which said prongs extend beyond the surface of the backing member; actuating means for selectively bringing said prongs and backing member together with said fibrous layer in the space therebetween, so as to cause the prongs to 'move into their extended positions and penetrate said layer against said backing member after said prongs have penetrated said layer and for continuing said pressure while the prongs are being Withdrawn from the layer and until after their withdrawal is complete, whereby the fibers are moved not only laterally but also along their respective center lines, with respect to other fibers in said layer, so as to permit the rearranged fiber segments to remain in mechanical equilibrium in their new positions.

13. Apparatus for producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: a backing member; a group of prongs arranged in locations corresponding to said pattern of holes, said group or" prongs having a withdrawn position spaced from said backing member and an extended position in which said prongs extend beyond the surface of the backing member; actuating means for selectively bringing said prongs and backing member together with said fibrous layer in the space therebetween, so as to cause the prongs to move into their extended positions and penetrate said layer to move se ments of some of said fibers laterally in the layer, and for selectively moving them apart; means for initially pressing the fibers of said layer against said backing member after said prongs have penetrated said layer and for continuing said pressure while the prongs are being withdrawn from the layer; said actuating means including control means for causing said actuating means to substantially withdraw said prongs from said layer before said pressure is released, whereby the fibers are moved not only laterally but also along their respective center lines, with respect to other fibers in said layer, so as to permit the rearranged fiber segments to remain in mechanical equilibrium in their new positions.

14. A machine for producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: a backing member; a group of prongs arranged in locations corresponding to said pattern of holes, said group of prongs having a Withdrawn position spaced from said backing member and an extended position in which said prongs extend beyond the surface of the backing member; actuating means for selectively bringing said prongs and backing member together with said fibrous layer in the space therebetween, so as to cause the prongs to move into their extended positions and penetrate said layer to move segments of some of said fibers laterally in the layer, and for selectively moving them apart; said actuating means including control means for selectively causing said actuating means to move said prongs into said layer until they have penetrated to substantially their full length and for selectively causing said actuating means to substantially withdraw said prongs from said layer before the pressure to be hereinafter described is released; means for initially pressing the fibers of said layer against said backing member after said prongs have penetrated said layer and for continuing said pressure while the prongs are being withdrawn from the layer; whereby the fibers are moved not only laterally but also along their respective center lines, with respect to other fibers in said layer, so as to permit the rearranged fiber segments to remain in mechanical equilibrium in their new positions.

15. A machine for producing a nonwoven fabric having a predetermined pattern of holes from a layer of irregularly arranged, overlapping fibers which comprises: a backing member; a group of sharp, tapered implements arranged in locations corresponding to said pattern of holes, said group of tapered implements having a withdrawn position spaced from said backing member and an extended position in which said implements extend beyond the surface of the backing member; actuating means for selectively bringing said tapered implements and backing member together with said fibrous layer in the space therebetween, so as to cause said implements to move into their extended positions and penetrate said layer to move segments of some of said fibers laterally in the layer, and for selectively moving them apart; said actuating means including control means for selectively causing said actuating means to move said tapered implements into said layer until they have penetrated to substantially their full length and for selectively causing said actuating means to substantially withdraw said implements from said layer before the pressure to be hereinafter described is released; means for initially pressing the fibers of said layer against said backing member after said tapered implements have penetrated said layer and for continuing said pressure while the implements are being withdrawn from the layer, whereby the fibers are moved not only laterally but also along their respective center lines, with respect to other fibers in said layer, so as to permit the rearranged fiber segments to remain in mechanical equilibrium in their new positions.

References Cited in the file of this patent UNITED STATES PATENTS 1,706,535 Marble Mar. 26, 1929 2,004,725 Johnson June 11, 1935 2,377,564 Lundgren June 5, 1945 2,429,486 Reinhart Oct. 21, 1947 2,672,672 Slaw Mar. 24, 1954 FOREIGN PATENTS 458,224 Great Britain Dec. 15, 1936

Claims

7. THE METHOD OF PRODUCING A NONWOVEN FABRIC HAVING A PREDETERMINED PATTERN OF HOLES FROM A LAYER OF IRREGULARLY ARRANGED, OVERLAPPING FIBERS WHICH COMPRISES: PUSHING SEGMENTS OF FIBERS IN SAID FIBROUS LAYER LATERALLY FROM EACH LOCAL AREA OF THE LAYER CORRESPONDING TO ONE OF THE HOLES IN SAID PREDETERMINED PATTERN, INTO CLOSER PROXIMITY AND INCREASED PARALLELISM WITH SEGMENTS OF OTHER FIBERS IN POSITIONS SURROUNDING SAID LOCAL AREA, BY APPLICATION OF MECHANICAL FIBER REARRANGING FORCES HAVING COMPONENTS PARALLEL TO SAID FIBROUS LAYER, SAID FORCES BEING APPLIED FIRST ONLY AT THE CENTER OF SAID AREA AND THEREAFTER AT POINTS PROGRESSIVELY NEARER THE PERIMETER OF THE AREA; AFTER THE DISTANCE OF THE POINTS OF APPLICATION OF SAID FIBER REARRANGING FORCES FROM THE CENTERS OF THEIR RESPECTIVE LOCAL AREAS HAS REACHED A MAXIMUM, MECHANICALLY CONFINING SAID REARRANGED FIBER SEGMENTS AGAINST LATERAL MOVEMENT FROM THEIR NEW POSITIONS BACK TOWARD THEIR ORIGINAL POSITIONS IN THE LOCAL AREAS FROM WHICH THEY WERE PUSHED; PRESSING SAID FIBROUS LAYER BETWEEN TWO COMPLEMENTARY SURFACES SO THAT THE REARRANGED FIBERS WILL NOT ONLY HAVE MOVED LATERALLY BUT ALSO WILL MOVE ALONG THEIR RESPECTIVE CENTER LINES, WITH RESPECT TO OTHER FIBERS IN SAID LAYER, AND THE REARRANGED FIBER SEGMENTS WILL REMAIN IN MECHANICAL EQUILIBRIUM IN THEIR NEW POSITIONS; TERMINATING SAID CONFINEMENT OF THE REARRANGED FIBER SEGMENTS AGAINST MOVEMENT BACK INTO THE AREAS FROM WHICH THEY WERE ORIGINALLY PUSHED; AND RELEASING THE PRESSURE EXERTED BY SAID TWO COMPLEMENTARY SURFACES UPON THE REARRANGED FIBERS COMPRISING THE RESULTING NONWOVEN FABRIC.