DK145991B - DEVICE FOR CHANGING THE WIDTH AND THICKNESS OF A COAT OF FIBER FIBER - Google Patents

Description

145991

The invention relates to an apparatus for changing the width and thickness of a web of textile fibers, said apparatus having a plurality of spaced apart spacers mounted so that they can rotate in planes with divergent or converging orientation relative to the direction of travel of the web, and which, on their perimeter, carries radially projecting projections which are spaced apart and which can be engaged with the web.

In the manufacture of nonwoven fabrics, a web of fibers formed by carding patches or bits of raw material is continuously passed through various processing steps, e.g. binding step such that eventually the desired final product is formed. However, since the methods used to make nonwoven materials today generally produce fibrous webs of relatively standard dimensions, for the sake of efficiency or simply to obtain a certain web width, it has become a problem to change this width under the following processing steps. Eg. For example, many embodiments of a machine containing a stretchable carrier area have been used for this purpose, wherein the web is stretched or made wider across the expandable carrier area of the machine.

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However, such device types are subject to machine damage due to the constant voltage and load applied, and these machines are also slow and it is difficult to control the width of the webs coming out from there.

Another type of apparatus which has been used for this purpose is a machine which is disclosed in the specification of US Patent No. 4,197,117.

2,709,282, and having a plurality of discs mounted on a grooved stationary shaft, wherein the inelastically fastened discs are oriented along the divergent lines defined by the grooves. On each plate, a plurality of needles are attached to the outer periphery which penetrate the fiber web and extend the web as it travels along the divergent lines. The individual discs contain openings which are aligned and a rod extends through the openings on the discs and at its opposite ends are connected to a pair of gears which are freely mounted on the stationary shaft around which they can rotate. The discs are rotated in this way and penetrate, as described above, into the web, bringing along the divergent lines formed by the thus-grooved shaft. However, this machine type suffers from a number of shortcomings. Eg. the needle-shaped perforation means causes undesirable holes in the web which adversely affect the web's strength; In addition, in order to change the width of the web in such an apparatus, it is necessary to work and groove a whole new set of washers and shaft to replace the washers and shaft of the machine (an expensive and time-consuming project at best). In addition, the individual discs cannot be moved or changed once they are mounted in the grooves of the shaft.

DE patents 291,047 and 300,550 describe an apparatus in which the discs are permanently held in a certain directional position. Thus, this apparatus must be completely remodeled if it is desired to use it for the manufacture of a second change of web width.

In the specification of DK Patent Application No. 1290/66, an apparatus of a completely different kind to the apparatus of the present invention is described, which known apparatus is provided with a roller having a smooth web-engaging surface and carrying a plurality of discs arranged with different degrees of obliquity.

Thus, while it is known to treat a fibrous web so as to change its width and thickness, the 20 devices so far described are not readily adjustable for changing the web width produced. In some cases, they also tend to tear or otherwise damage the web.

According to the present invention, there is provided an apparatus which can be readily adjusted to produce various changes in the web width produced and which does not tear or otherwise damage the web produced.

This is achieved with the apparatus of the kind mentioned in the preamble, which is characterized in that the discs are mounted on a power-driven shaft by means of a cardan suspension, that the projections are flexible and that a cam-like control means is provided for joining the engage with and control the orientation of the slices.

Thus, in the apparatus according to the invention, the circumference of each disc can move in a cardiac or gyroscopic motion around the shaft. As the disks of the guide are directed diverging away from an approaching path, the width of the web is increased at passage. Once oriented in a particular way, the plates are held in this position by the control means which produces a certain desired degree of divergence and consequent width increase of the nonwoven fabric. Using the same shaft and washers, the degree of stretching at a particular location can be changed simply by orienting the plates differently by means of the guide. A fabric web moving toward the discs on the convergence side of the discs is gripped by the flexible protrusions encountered on this side and evenly drawn along the divergent lines so as to increase the width of the web while decreasing its thickness.

An embodiment of the apparatus according to the invention is characterized in that each cardan suspension comprises a pair of pivots extending radially from the shaft and an inner ring which is arranged on the pivot pins and having pivot points located at the inner edge of a disc. , which is displaced 90 ° relative to the pivots.

Another embodiment of the apparatus according to the invention is characterized in that the outer discs carry more projections than the inner discs.

A third embodiment of the apparatus according to the invention is characterized in that the outer discs have a larger diameter than the inner discs or have finger extensions supporting the projections.

A fourth embodiment of the apparatus according to the invention is characterized in that the control means, in addition to teeth which engage in the region between the discs, have extensions which are arranged behind and inclined about 45 ° with respect to the teeth.

A more detailed description of embodiments of the invention will now be given with reference to the drawing, in which: Fig. 1 is a perspective view of the apparatus according to the invention 25 for changing a web; 1 FIG. 3 is a plan view of a disk mounted on a shaft as used in the apparatus of the invention; FIG. 4 is a perspective view of another embodiment 30 of the guide plate or cam shown in FIG. 2; FIG. 5 is a plan view of another embodiment of a disc.

FIG. 1 shows the apparatus according to the invention, in which a web of fibers 35 11 for producing nonwoven fabrics by means of a conveyor belt 12 or the like is fed to a rotating set of discs 13, connected to a rotatable mechanically driven shaft 14 on a support. The discs 13 are oriented in a divergent direction away from the conveyor belt 12 which advances the web to be stretched, and is held in this position by guide means; sisom guide plates 15 and 16 of plastic material.

The angle of divergence of each disc can be adjusted separately, since the discs 13 are mounted on the rotatable shaft 14 by means of a 5-stage hinge arrangement capable of performing a gyroscopic or cardiac movement, wherein a first or inner ring 17 is connected to the shaft 14 by a pair of pivots. 19, which protrudes 180 ° apart from the shaft and allows this ring and an associated outer ring to pivot back and forth along a curved path 10 in the horizontal plane of the shaft 14 (see arrow A p in Fig. 3). A second or outer ring 18 is then fixed at pivot points 21 located on the perimeter of the inner ring 17 and displaced 90 ° from each guide bolt 19, the outer ring 18 containing two openings on its inner edge 180 ° degrees apart to receive 15 pivot points 21, thereby facilitating the free, curved vertical plane of the disc (see arrow B in Fig. 3). For the purposes of this invention, the terms pivot points and pivots denote spherical structural shapes, but any structure which permits the relatively free, curved, plane movement about an axis such as shown in the drawing is acceptable. Such a disk construction has the advantage of allowing the circumference of the discs 13 to move gyroscopically freely over a wide range of divergent and converging lines at a rotation of the discs of 360 °.

On the circumference of the discs 13 are a plurality of spaced flexible projections 22 which extend radially outwardly therefrom. These projections 22, which rotate with the discs 13 driven in the clockwise direction, readily grasp an arriving web of fibers 11 and bring it along the divergent lines causing the web's width to increase while simultaneously reducing its thickness 30. An abduction roller 23 then assists in removing the web 11 from the discs 13 and directing it to another conveying system 24 where it is advanced for further processing as desired.

The operation of the apparatus according to the invention is perhaps better understood from the figures 2 and 3 of the drawing, in which the rotatably driven shaft 35 carries the plurality of discs 13 in divergent direction as shown by the arrow. The angle of divergence is determined and maintained by means of guide plates 15 and 16, which are shown herein in the form of a comb at the front and rear regions of the discs 13.

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The individual teeth, such as 15a and 16a, on the guide chambers 15 and 16 can be placed at a slightly different angle from the other teeth so that the disc held between them is placed at a divergence angle different from the other discs. This option 5 helps prevent the emergence of weak areas in the stretched web. Eg. it may be observed during a test run that a particular portion of the web is stretched to a greater extent than desired, and this can be prevented simply by changing the divergence angle of the particular teeth controlling the disc or discs causing problems, this area being thereby less stretch or adjacent area is given more stretch. The guide chambers 15 and 16 can advantageously be made of a self-lubricating plastic material, such as high molecular weight polyethylene, which will not cause excessive friction upon contact with the rotating discs 13. However, it should be noted that almost any kind of durable material can be used for this purpose. Of course, the design of the guide comb should be such that the angles of the teeth can be adjusted individually by a technique which is well known to those skilled in the art.

The disk drive mechanism on the shaft can be seen in FIG. 2, wherein 20 all washers 13 are initially placed on the shaft 14 in a plane perpendicular to the shaft. The discs 13 were then brought to converge at one end and held in that position by the guide cam 16 at that end and by the guide cam 15 at the resulting divergent end of the discs. When the washers 13 are pulled together in this way, it can be seen that the inner rings 17 of the washers all incline toward the center of the array. However, it should also be noted that these new rotatable discs can be turned completely opposite simply by changing the angles of the control cam. In this way, a fabric web can be made narrower and, consequently, thicker and heavier if 30 such properties are desired.

Another method for controlling the thickness and uniformity of the web is to control the distance between the flexible projections on the outer diameter of the discs 13. For example. FIG. 2, that the two end discs on each side contain many more projections 13 than the other 35 discs mounted on the shaft 14, which were made to prevent the outer edges of the web from curling, which can occur when each disc 13 the device has the same number of projections .22. The additional projections on the outer discs also ensure that the incoming web is properly gripped by the projections as the spread 6 145991 begins. The number of protrusions 22 p in each of the other disks can also be varied if it is found to be favorable. Eg. For example, it can be observed that part of the web is stretched too much or not enough and the number of projections 22 can be increased or decreased 5 respectively to achieve the desired uniformity of the web. It should be noted that the greater the number of projections on the discs, the more uniform the stretching of the web becomes, and consequently the weight distribution over the entire width of the stretched web becomes more uniform.

When all the discs have the same diameter, they form a convex curve from one end to the other when viewed from above, see FIG.

2. This can cause certain problems when the web is received and / or detached from the flexible projections 22, since the edge velocities at the different locations are different as the rotational radii of the discs are different. Further, as the web will not land on all the discs at the same moment, it takes a short time for the web to be absorbed by the outer discs, which may allow it to flutter loosely causing heavy edges, loss of stretchability and lack of uniform weight distribution over the web. width. This problem can be avoided in at least two ways. Eg. For example, the outer discs may have increasing diameters such that a substantially straight line is formed when the discs are viewed from above.

In this way, the web can be recorded and removed from all the discs at substantially the same time. An alternative to enlarging the discs is shown in Fig. 5, where extending fingers 41 with flexible projections 42 are mounted on the rim of the disc 43 so as to increase its effective diameter. At least two discs so constructed can be used to produce a substantially straight line of the discs when viewed from above, allowing the web to be uniformly and simultaneously grasped by the discs.

Another technique for controlling the width and thickness of the web using the new apparatus of the invention is simply to control the location at which the web contacts the rotating discs. This can be accomplished simply by introducing the web onto the discs in a higher position than those described above, so that the web will be removed from the discs before being stretched to its maximum width, however, this technique only affects the web width and thickness and not necessarily its uniformity.

The projections 22 are of flexible material which will not penetrate or break through the web, but rather will grip the web easily and advance it with a bold stretching motion. Neoprene 70, a trade name for a synthetic rubber material sold by du Pont, is preferred for this purpose, but other rubber, rubbery or non-rigid plastics materials will work similarly, albeit with somewhat less desirable results.

FIG. 4 shows another embodiment of the guide cam, wherein the cam 31 has arm-like protrusions 33 at approximately an angle of 45 ° C from the slots behind each tooth 32. This structure prevents loose or extraneous pieces of web from falling between the discs and possibly blocking the apparatus.

A preferred apparatus for increasing the width of a 102 cm web to approx. 254 cm can be as follows: A rotatable metal shaft with a diameter of approx. 20 cm has mounted 43 discs, each disc having a diameter of approx. 183 cm and is connected to the shaft by the guide bolts described above. The discs are arranged on the shaft with distances of 4.5 cm, each disc parallel to the closest disc and perpendicular to the horizontal plane through the shaft. Flexible protrusions of Neoprene 70 with a height of less than 2.5 cm extend radially from the circumference of each disc at a distance of 15.2 cm from each other, while the two discs located at each end of the array contain projections extending radially outwards at a distance of 5.1 cm from each other such that curvature of the outer edge of the stretched web is prevented. Control cams are then provided which cause the discs to converge in the receiving portion of the apparatus, each disc being held 2.5 cm from each adjacent disc at that end while the discs being kept 6.4 cm apart in the most divergent region of the discs. . At this mite, the width of a web of 102 cm will be increased 2.5 times or to approx. 254 cm.