US3372447A - Process and apparatus for needle felting non-woven fabrics - Google Patents

Description

.March 12, 1968 J, A, WILLIAMS ETAL 3,372,447

PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS 4 Sheets-Sheet 1 Filed Feb. 28, 1966 mmmmmlzammmm 5 W m M .7 r z g 0 I K F: WM M March 12, 1968 J. A. WILLIAMS ETAL ,3

PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS Filed Feb. 28, 1966 4 Sheets-Sheet 2 ill? ,1

FOR/VEYS March 12, 1968 J. A. WILLIAMS ETAL 3,372,447

PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS Filed Feb. 28, 1966 4 Sheets-Sheet s EMA 1 z( March 12, 1968 J. A. WILLIAMS ETAL 3,372,447

PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS Filed Feb. 28, 1966 4 Sheets-Sheet 4 Q a g United States Patent 3,372,447 PROCESS AND APPARATUS FOR NEEDLE FELTING NON-WOVEN FABRICS James A. Williams, Pearisburg, Va., and Ralph H. Balch,

Charlotte, N.C., assignors to Celanese Corporation of America, New York, N.Y., a corporation of Delaware Filed Feb. 28, 1966, Ser. No. 530,446 16 Claims. (Cl. 28-4) ABSTRACT OF THE DISCLOSURE Non-woven fabrics are needle punched in a continuous manner by a plurality of needles mounted on a revolving drum. The needles enter the moving non-woven fabric at an angle less than 90 with respect to the fabric and are withdrawn from the fabric in a substantially longitudinal motion.

and a mat is built upon the conveyor of many fibers laid on top of each other. Very few of the fibers extend vertically through the mat and, as a result, there is practically no cohesion between the fibers in the mat. The loose mat is not self-sustaining and would disintegrate if it were removed from the conveyor. One method of improving the structural integrity of the mat is to pierce the mat with a plurality of needles. Usually, the needles have barbs and when they are forced through the mat, the

barbs catch some of the fibers and draw them downward through the mat, so that the fibers become entangled with other fibers across the thickness of the mat.

In conventional needling apparatus, the needles are mounted in a frame which reciprocates vertically with respect to a horizontally moving mat. The progress of the mat is stopped while the needles are lowered into the mat and the mat is started again after the needles have been withdrawn from the mat. This step motion of the conveyor is necessary because the needle frame is not mounted for movement along with the conveyor. The step motion of the conveyor necessarily limits the rate of production of non-woven fabrics. Another deficiency of the reciprocating needle arrangement is that the needles enter the fabric substantially perpendicularly and thus engage only the fibers that are directly in the path of the needles. In order to get maximum entanglement of the fibers by the needling process, therefore, it is necessary to utilize a great many needles closely spaced together. This greatly increases the cost of the apparatus, it close entanglement of fibers is desired.

Accordingly, it is an object of this invention to provide an improved needling process and apparatus.

It is a further object of this invention to provide a method and apparatus for needling non-woven fabrics or mats on a conveyor while continuously advancing the conveyor.

It is a still further object of this invention to provide a method and apparatus for causing maximum entanglement of fibers in non-woven fabrics or mats.

3,372,447 Patented Mar. 12, 1968 These objects are accomplished in accordance with the preferred embodiment of the invention by mounting a plurality of needles on a revolving drum and changing the positions of the needles with respect to the non-woven mat as the needles approach and move away from the mat. In one embodiment, the needles are offset with respect to the axis of rotation of the drum and are quickly withdrawn from the mat by longitudinal motion of the needles. The motion of the needles is controlled in such a manner that the needles penetrate the mat and are quickly withdrawn while the drum is rotating and the mat is moving continuously under the drum. In another embodiment of the invention, the needles are mounted for swinging motion in radial planes with respect to the drum. The positions of the needles are controlled so that they point toward the mat as they approach the mat, but the mat moves at a slower speed than the drum, which causes the needles to swing rearwardly prior to being withdrawn from the mat. Thus, the needles are withdrawn approximately longitudinally to produce maximum entanglement of thefibers. The needles are barbed for catching fibers upon movement into the mat and also upon movement back out of the mat. In this second embodiment of the invention, a greater degree of entanglement of fibers is produced at the center of the that than at the surface of the mat.

These preferred embodiments of the invention are illustrated in the accompanying drawings, in which:

FIGURE 1 is a schematic view of the needling apparatus of this invention;

FIGURE 2 is a front elevational view of the needling drum;

FIGURE 3 is a cross sectional view of the drum along the line 33 in FIGURE 2;

FIGURE 4 is a cross sectional view of the drum along the line 4-4 in FIGURE 3;

FIGURE 5 is a cross sectional view as in FIGURE 3, but of a modified form of the invention; and

FIGURE 6 is across sectional view of the modified drum along the line 6-6 in FIGURE 5.

Non-woven fabrics are made up of loose fibers that are joined together by random entanglement rather than weaving. One method of producing non-woven fabrics is to deposit the fibers on a moving conveyor 2, as shown in FIGURE 1. The fibers may be deposited on the conveyor 2 as it passes through a chamber 4. The fibers are laid on top of each other to form a mat 6 on the conveyor 2. A revolving drum 8 is mounted over the conveyor 2 and extends transversely across the mat 6.

The drum 8, as shown in FIGURE 2, includes an outer cylinder 10 which is mounted for rotation on a stationary, non-rotating shaft 12. The shaft is supported tionary shaft 12.

A plurality of needle assemblies 26 are arranged in rows extending around the circumference of the cylinder 10 and the rows of needle assemblies 26 are spaced apart uniformly along the length of the cylinder 10. The spac- 3 ing between the rows of needle assemblies 26, as shown in FIGURE 2, is merely illustrative. The needle assemblies may be positioned closer together or further apart, as required. Preferably, the needle assemblies in adjacent rows are staggered.

Referring to FIGURE 3, the needle assemblies 26 include a barbed needle 28 and a needle holder 30. The needles have barbs pointing in opposite directions. In each assembly 26, the base of the needle 28 is secured in a plug or cap 32. The needle holder 30 is in the form of a hollow tube and the cap 32 is secured on the end of the tube by a conventional bayonet fastener 34, or any other suitable means. The cylinder has a plurality of internal bosses 36, each of which has a tangential bore 38 in which the holder 30 is mounted. The needles 28 are pointed in the direction of rotation of the cylinder 10. The central axis of each needle is positioned at approximately right angles to a radius of the cylinder 10. With this orientation, the needles enter the mat at an angle less than 90 with respect to the mat surface. Preferably, the angle of entry is between 30 and 60.

The holders 30 are received in the respective bores 38 and each of the holders is spring-biased toward movement inwardly with respect to the cylinder 10. A spring 40 is mounted in each of the holders adjacent the closed end and the holders have a longitudinal slot 42 through which a screw 44 extends. The screw 44 is threaded into a hole in the cylinder 10 and the slot 32 allows the holder to move longitudinally relative to the screw 44. The screw compresses the spring 40 against the closed end of the needle holder 30. Thus, the spring 40 urges the holder inwardly with respect to the cylinder 10.

The positions of the needle holders 30 with respect to the cylinder 10 are controlled by cam followers 46. As shown in FIGS. 3 and 4, the cam followers 46 are mounted for swinging movement about a pivot pin 48 which is rigidly supported by a ring 50 extending radially around the interior of the cylinder 10. The ring 50 is welded or otherwise secured to the interior surface of the cylinder 10 and rotates with the cylinder. Each of the cam followers 46 has an arm 52 which bears against a stationary annular cam 54. The cam 54 is supported by a hub 56 with radial spokes 58 interconnecting the hub and the cam. The hub 56 is rigidly secured to the stationary shaft 12 by means of a key 60 which is received in a key slot 62 in the shaft 12. Preferably, each of the rows of needle assemblies has a separate cam 54.

The cylinder 10 is mounted on the shaft 12 for rotation relative to the shaft. The mounting for the cylinder includes a hub 64 and radial spokes 66 between the hub and the cylinder. The hub 64 turns freely about the shaft 12. Preferably, a plurality of hubs and spokes are spaced along the length of the cylinder 10. In order to provide staggered rows of needle assemblies, the hubs 56 are angularly offset from the hubs 56 of adjacent needle cam assemblies in such a manner that the path of the needles in each of the cam assemblies is substantially the same with respect to the mat 6.

The profile of the cam surface is shown in FIGURE 3. The cam follower arms 52 are urged against the surface of the stationary cam 54 by the springs 40 in each of the needle holders 30. As the needle assemblies move clockwise with the cylinder 10, as viewed in FIGURE 3, the needle holders 30 are fully extended with respect to the cylinder 10 as they approach the mat 6. As the needles enter the mat 6, the respective cam followers approach the fall portion of the cam 54 which causes the followers 46 to swing about the pivot pin 48. As the cam follower arm 52 passes over the fall portion of the cam, the follower 46 swings to its lowermost position on the cam, allowing the needle holder 30 to be retracted rapidly into the cylinder 10 by the spring 40. This movement causes the needle to be withdrawn from the mat 6 in a substantially longitudinal motion. Then, after the needle 28 has moved clear of the mat 6, the cam follower 4 is pivoted by the rise portion of the stationary cam back t the extended position where it remains until the needle assembly again approaches the mat 6.

Preferably, the needles 28 are sutficiently long to pierce the full depth of the mat and project a short distance below the mat, as shown in FIG. 3. In order to prevent interference between the needles and the conveyor 2, grooves 68 may be provided in the conveyor 2. Also, since barbs on the needle 28 engage the fibers in the mat to draw them transversely along the direction of movement of the needles, there may be a tendency for some of the fibers to remain on the needles when the needles are withdrawn from the mat. Accordingly, it may be necessary to provide a stripper plate 70 above the mat 6. The plate 70 has longitudinal slots 72 through which the needles pass. The slots 72 are preferably narrow, so that they will pull off any fibers that are retained on the needles as they are withdrawn from the mat.

In operation, the speed of the conveyor 2 is adjusted to advance the mat 6 at a uniform speed under the drum 8. The drum has approximately the same surface speed or a slower surface speed than the mat 6. The clockwise rotation of the cylinder 10, as viewed in FIGURE 3, advances the needles 28 sequentially into the mat. When the needles have pierced the mat 6, they are immediately retracted by swinging movement of the cam followers 46 in moving through the fall portion of the cam 54. The spring loaded needle holders are urged inwardly with respect to the cylinder 10 by the internal springs 40 as they reach the point of maximum penetration of the mat. Then after the needles 28 have been withdrawn from the mat 6, the cam followers 46 rotate to move the needles 28 toward the outermost position where they remain until they engage the mat again.

A modified form of the invention is shown in FIG URES 5 and 6. The drum 8, as shown in FIGURES 1, 2 and 3, is modified to include a cylinder 74, on which are mounted needle assemblies 76 that are arranged in substantially the same manner as the needle assemblies 26, shown in FIGURE 2. The needle assemblies 76 are mounted for swinging movement relative to the cylinder 74 and the positions of the needles are controlled by a stationary cam 78 inside the cylinder 74.

Each needle assembly 76 includes a needle 80 which has its base mounted in a hub 82 and an arm 84 which projects outwardly on the opposite side of the hub. On the end of the arm 84, there is a cam follower 86 which projects laterally from the arm 84. The hubs 82 are mounted for swinging movement relative to the cylinder 74 by hearing blocks 88 on opposite sides of the hubs. Openings 90 are provided in the cylinder 74 for receiving the respective hubs 82. Of course, other suitable arrangements may be provided for mounting the hubs 82 for pivoting movement relative to the cylinder 74.

As shown in FIG. 6, the cylinder 74 is mounted for rotation on the shaft 12 by means of a hub 92 with radial spokes 94 extending between the hub 92 and the cylinder 74. The stationary cam 78 is also supported on the shaft 12 by means of a hub 96. The hub 96 is prevented from rotating relative to the shaft 12 by a conventional key 98 which is received in a key slot 100. Spokes 102 project outwardly from the hubs 96 for supporting the stationary cam 78.

The cam 78 has an annular groove 104 in the side adjacent the needle assemblies 76. The groove 104 includes a narrow portion 106 and a wide portion 108 interconnecting the ends of the narrow portion 106. The narrow portion 106 of the groove 104 is slightly wider than the diameter of the cam followers 86, while the wide portion 108 is sufficiently wide to allow the arms 84 to swing freely about the hubs 82. At the junction of the wide portion 108 and the narrow portion 106, the side of the groove 1438 forms a rise cam surface 110 which swings the needle around to point in the opposite direction and guides the follower 86 into the narrow portion 106 of the groove.

As the cylinder 74 rotates, the needles 80 are guided into the mat 6, but while the cam follower is in the wide portion 108 of the groove 104, the needle is free to turn about the hub 82. The movement of the cylinder 74 at a greater surface speed than the mat 6 causes the needle to swing from a forwardly pointing direction to a rearwardly pointing direction, as shown in FIG. 5. Withdrawal of the needle occurs while the needle is pointing in a rearwardly direction. When the relative speeds of the cylinder 74 and the mat 6 are properly adjusted, the needles pierce the mat by substantially longitudinal movement of the needles relative to the mat. The needles are also withdrawn by substantially longitudinal movement of the needles and during such movement the barbs on the needles catch some of the fibers in the mat and draw them along the direction of movement of the needles. The needles have barbs pointing in opposite directions to catch the fibers as the needles pass into and back out of the mat 6.

The belt conveyor 2 under the mat 6 may be in the form of a plurality of individual belts 68 which are spaced apart sufiiciently to allow the needles 80 to pass between the belts. The gaps between the belts should be aligned with the rows of needle assemblies 76 on the surface of the drum. Also, a stripper plate 70 is preferably positioned above the mat to remove the fibers remaining on the needles after they have been withdrawn from the mat.

In operation, the speed of the mat 6 is adjusted to be slower than the surface speed of the cylinder 74. As the needle assemblies 76 approach the mat 6, the needles 80 are guided by the cam groove 104 to point toward the mat as shown in FIG. 5. The relative distance between the cylinder 74 and the mat 6 is adjusted, so that the pointed end. of the needle 80 enters the mat as the corresponding follower 86 enters the wide portion 108 of the cam groove 104. While the needle is in engagement with the mat, it swings to a rearwardly pointing position. After the needle has been withdrawn from the mat, the cam follower 86 of the needle assembly engages the rise portion 110 of the cam groove 104 to swing the needle 80 around so that it is in a forwardly pointing position before entering the narrow portion 106 of the groove 104.

The path of motion of the needles 80, as shown in FIGURE 5, causes a high degree of entanglement of fibers at the center of the mat adjacent the point about which the needles swing. At the surfaces of the mat, the needle moves transversely relative to the mat, causing a loose entanglement of fibers at the surfaces of the mat. The resulting mat resembles a napped woven fabric. This structure of the mat is desirable because of its good drape qualities and raised or napped surface.

It is apparent that the needles 28 and 80 of the apparatus of this invention enter the mat and remain in the mat for a considerably shorter duration than would be possible if merely radial needles were provided on the surface of the cylinder of the drum 8. Also, instead of sweeping through the mat, the needles penetrate the mat primarily in a longitudinal motion. Accordingly, the mat produced by the apparatus of this invention has a plurality of fibers that are drawn generally perpendicular to the direction of motion of the mat and are entangled with the adjacent fibers in the mat and the result is that the strength of the mat has been considerably increased. Furthermore, since the mat moves continuously during the needling operation, the apparatus achieves a high production rate and there is no need to provide for intermittent motion of the mat as is necessary with reciprocating type needling devices.

It is desirable for the points at which the needles penetrate the mat to be close together in order to obtain maximum entanglement of the fibers. As previously stated, the needle assemblies in adjacent rows may be staggered for this purpose. Another alternative is to provide a series of staggered drums 8 along the length of the mat 6 with the drums rotating in fixed angular relations with each other. Thus, the needles of the subsequent drums would penetrate the mat at points between the penetration points of the needles in preceding drums.

. While this invention has been illustrated and described in several embodiments, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.

We claim:

1. A method of needle felting a non-woven fabric comprising elfecting continuous motion of said fabric along a substantially straight path, piercing said fabric with needles, and withdrawing said needles from the fabric in a substantially longitudinal motion.

2. A method of needle felting a non-woven fabric according to claim 1 including moving said needles in an arcuate path.

3. A method of needle felting a non-woven fabric according to claim 2 including changing the position of said needles relative to said arcuate path while said needles are in engagement with said fabric.

4. A method of needle felting a non-woven fabric according to claim 1 including changing the orientation of said needles relative to said fabric while piercing said fabric.

5. A method of needle felting a non-woven fabric according to claim 4 including moving said needles and said fabric in substantially the same direction, said needles moving at a greater speed than said fabric.

6. Apparatus for needle felting non-woven fabrics comprising a plurality of needles, means for moving said needles in an arcuate path and means for changing the position of said needles relative to said path, whereby the needles are withdrawn from the fabric in a substantially longitudinal motion.

7. Apparatus for needle felting according to claim 6 wherein said moving means includes a drum, said needles being mounted in said drum, and means for rotating said drum.

8. Apparatus for needle felting according to claim 7 wherein said drum includes a cylinder and cam means, means mounting said needles in said cylinder, means for rotating said cylinder relative to said cam means, and means on said needless for engaging said cam means, whereby said cam means controls the position of said needles relative to said cylinder.

9. Apparatus for needle felting according to claim 7 wherein said needles are positioned generally tangentially of said cylinder.

10. Apparatus for needle felting according to claim 9 wherein said needle mounting means includes means cooperating with said cam means for individually displacing said needles longitudinally.

11. Apparatus for needle felting according to claim 8 wherein said needles are mounted for swinging movement relative to said cylinder, said cam means restricting swinging movement of said needles during a portion of each revolution of said cylinder and releasing said needles for swinging movement during another portion of each revolution.

12. In needle felting apparatus of the type having a movable conveyor on which non-woven fabrics are supported, a needle felting drum, a plurality of needles projecting outwardly from said drum, means for rotating said drum, said fabrics being in position on said conveyor to be pierced by said needles, and means for withdrawing said needles from the fabric by substantially longitudinal movement of said needles relative to said conveyor, said drum rotating continuously and said conveyor moving continuously relative to the drum.

13. The apparatus according to claim 12 wherein said conveyor supports said fabric on a substantially planar surface parallel to the central axis of said drum.

14. The apparatus according to claim 13 including means for guiding said needles into said fabric, said needles engaging said fabric while inclined relative to the plane of said fabric and pointing in the direction of rotation of said drum.

15. The apparatus according to claim 14 wherein said needles are mounted for swinging movement while in engagement with said fabric, said conveyor moving said fabric at a slower surface speed than that of said needles, whereby the fabric causes the needles to swing from forwardly inclined to rearwardly inclined positions.

16. Apparatus for needle felting according to claim 6 wherein said needles have barbs projecting in opposite longitudinal directions.

References Cited UNITED STATES PATENTS 5 2,920,373 1/1960 Gresham 2872.2 3,025,585 3/1962 Griswold 28-1 3,038,215 6/1962 Harwood 19-161 3,208,125 9/1965 Hall et al. 284

10 LOUIS K. RIMRODT, Primary Examiner.

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