NL1023621C1 - Press with ribbed knife roll and grooved counter roll for cutting fibres, has press ribs with cavities filled with adjustable pressure gas - Google Patents

Abstract

The press ribs (4) contain cavities (10) which can be filled with adjustable pressure air or gas via the roll core (14) and channels (15) in the knife roll (1). A method for cutting fibres (7) into pieces (8) comprises the use of knives (3) cooperating with grooves (6) in a counter-roll (2), whilst holding the fibres against the counter-roll using press ribs located in between the knives on the knife roll. The press ribs contain cavities which are closed at the end of the rolls and can be filled from the outside with adjustable pressure air or gas via the roll core and channels in the roll. An Independent claim is also included for the roll nip press used to carry out this method.

Description

Method and device with air-filled back pressure ribs I

for cutting fibers.

The invention relates to a method for cutting glass fibers or other fibers such as into pieces

for example carbon fibers, the fibers between I

a knife roller and a counter-pressure roller are passed through, I

which knife roller and counter-pressure roller in opposite I

turn direction with essentially equal

10 peripheral speed at which the blades of the knife roller are the I

push fibers into recesses of the counterpressure roller around the I

breaking fibers while the fibers are in place I

be held between the counter-pressure roller and I

back ribs which are between the knives on the knife roller I

15 are provided. To such a method and

In the Netherlands, patents have been granted under I

numbers 1010665, 1012286 and 1021947. I

In the existing embodiments, back pressure ribs become the same with each revolution of the knife roller

pressed down. I. Enters the material of the back pressure rib

thereby a repetitive voltage change, with I

a frequency equal to the rotation frequency of I

the knife roller. The depth of the depression of the rib is generally proportional to the force applied to it

impressions must be applied. However, it is desirable I

a high compressive force even with slight compression I

so that the fiber already at low I

impression is held sufficiently to hold the cut or I

30 be able to have a breaking operation take place. Furthermore, I

hysteresis occurs to a greater or lesser extent in the I

material of the printing ribs, which is at the expense of

of the effectiveness of the ribs, since they are not always I

10236211 I

I come back in their original form after the impression.

It is an object of the invention to provide a method for cutting fibers into pieces, which makes the pressing force of the pressure ribs against the counter-pressure roller adjustable, eliminates the hysteresis of the pressure ribs in the existing method, makes the fiber disintegrate better after cutting. and is more effective.

In a preferred embodiment, the fiber is guided between a knife roller, on which a plurality of substantially radially oriented knives are arranged around the circumference, the cutting lines of which are substantially parallel to the roller axis, and a counter-pressure roller (also referred to as pressure roller I), which is rollers with the same peripheral speed I are driven in mutually opposite directions, the fiber being clamped between back pressure ribs, which are located on the knife roller between the knives, and the counterpressure roller, the knives I breaking the fiber (s) through the fiber (s) ) into the grooves of the I counter-pressure roller, over which grooves the I push-back ribs hold the fiber (s). During this breaking, the blades cannot touch the counter-pressure roller. The distance between the knives and the counter-pressure roller, or between the knives and the edges or bottom of the grooves in the counter-pressure roller, is in all directions greater than the thickness I of the fiber (s) to be cut.

The fiber is engaged at two places by the two rollers H, while the knife is pressed against the fiber between those two places. The fiber is thus bent over the cutting edge of the knife and then broken.

II 0 2 Λ fi 9 1 I

3 I

The point of engagement is preferably between the I

back pressure rib and the counter pressure roller, as seen in the I

direction of movement, closer to the cutting edge of the I

previous knife than at the cutting edge of the one behind it

5 horizontal knife. I

In a preferred embodiment, the circumference of the I

print rib in cross-section mainly in the form of I

a semicircle. On the outer circumference, roughness I

10 are provided in the form of random I

unevenness / or in the form of ribs or recesses I

according to a desired pattern. I

In a preferred embodiment, the half-round rib becomes I

15 confirmed / as described in said I

Dutch patents by using an I

profiling on the knife roller around which a recess I

of the rib on the inward-facing side exactly I

or fits with a small excess. The recess fits I

20 accurate to the profile of the knife roller but is in I

H

this preferred embodiment on the outward facing I

side of the profile of the roller made wider, I

creating a cavity. The cavity can be at the ends I

of the rib to be sealed to allow an air containment

25. These air inclusions can at I

preferably from outside via channels in the knife roller I

be brought and kept under a desired pressure, al

or not while the machine is running. The I

wall around the recess of the rib is preferably I

30 is relatively thin with respect to the diameter of the rib I.

or the distance between two blades, and is provided with an I

reinforcement in the form of a membrane or a fabric, which I

bending but does not allow stretching. In this way I

arise semi-circular ribs that can be filled with air. I

<1 A O T C O 4 i I

In a preferred embodiment, a profiling is applied to the counter-pressure roller, which ensures that the H-back pressure rib is evenly bent when pressed, to prevent wear and does not load the blades sideways. This profiling also bends the fiber during the cutting, whereby the mutual cohesion within the fiber is reduced, and the fiber falls apart better after the H cutting. In practice, it has also been found that H 10, due to the strong bending of the fiber against H, the push-back rib, and then the relaxation and bending back of fiber and rib after cutting, the fiber I releases the rib well and contamination of the knife roller. I is prevented by sticking cut fiber.

The knives, grooves and profiling in the knife roller and counter-pressure roller are preferably not arranged parallel to the I axes, but arranged in a spiral (small angle to the axis), the angle of rotation corresponding to the length of the roller corresponding to one or two times the pitch of the knives and grooves, so that impact loads are prevented during operation.

In another preferred embodiment, the supplied air is thermally conditioned and the knife roller I is provided with an air circulation system, whereby the temperature in the cutting process can be controlled.

In another preferred embodiment, the cavity to be filled with air is not combined with the recess or narrowing of the back pressure rib that is used for attachment to the knife roller, but is separately

I, as described, for example, in Fig. 5A

of patent 1010665.

I 1 02 3 6 2 1 *

The invention further relates to a device I

for cutting fibers into pieces, provided with a

knife roller, with a plurality of substantially radially oriented H

5 knives whose cutting lines are essentially parallel H

lie on the axis of the roller, and a counter-pressure roller, H

which rollers with equal circumferential speed in mutual H

are drivable in the opposite direction, with a

fiber is divided into pieces by a knife against the H

10 to press fiber and the blades are positioned such and H

the counter-pressure roller is shaped such that the blades H

against cutting between the rollers during cutting

fiber can print without touching the counter-pressure roller. The I

back pressure ribs have cavities in which air or gas on an H

Desired pressure from outside can be applied via H

channels in the knife roller. H

To clarify the invention, under H

reference to the drawings, an exemplary embodiment

20 of a fiber cutting device are H

described. In the drawings, all details, which are not I

contribute to a better understanding of the functioning of I

omitted the device. I

Figure 1 is a cross-section perpendicular to the axes of the

rolling the fiber cutting device. I

Figure 2 is a cross-sectional view of back pressure rib 4 I

perpendicular to the axes of the rollers. The scale of Figure 2 I

is larger than that of figure 1. I

30 I

According to Figure 1, the device consists of one

knife roller 1, a counter-pressure roller 2, which according to the

arrows indicated direction rotate about their respective axes with equal peripheral speed. On the knife roller

1A9U91 I

Knives 3 are provided, the cutting edge I of which is substantially parallel to the axis of the roller 11 and which is approximately the same length as the roller 1. The knives I 3 are oriented substantially radially outwards with respect to the knife roller 1. I also have press-on ribs 4 whose center lines I are substantially parallel to the cutting edges of the adjacent knives 3 and which are approximately the same length as the roller 1.

In order to further clarify the composition of the knife roller 1, the back pressure ribs 4 have been omitted over a part of the circumference of the knife roller 1 in Figure 1.

The push-back ribs 4 are fixed around a profile 5 protruding from the knife roller that fits into the recess I 9 (numbering only shown in Figure 2) of the rib 4. The edges 12 along the recess 9 of ribs 4 are thickened so that they fill the space between the blades 3 and I the profile 5. If necessary, the thickness of edges 12 of rib 4 is slightly larger than the said space in order to be able to clamply mount the blades. This method of attaching the push-back ribs is known from patent I 1012286.

The recess 9 is made larger than profile 5 on the outwardly directed side of the profile 5. This creates a cavity 10. At the ends of the ribs 4 those cavities 10 become between ribs 4 and profiles 5 of I roller. 1 sealed. Via roller 1, the ribs 4 filled with air or another gas are brought through the core 14 of the roller 1 and channels 15 which run through profiles 5, filled with air or another gas and brought under a desired pressure.

The wall 11 of the rib 4 is relatively thin with respect to the size of the rib, preferably less than I 1/10 of the diameter of the rib 4.

I 1 02 3 62 1

The counterpressure roller is provided with a convex profiling Η 13 that cooperates with back pressure rib 4. Η

The counter-pressure roller 2 is provided with H at its circumference

5 grooves 6 which extend substantially axially towards H

extend approximately the length H with respect to roller 2

of roller 2. H

During the rotation of the rollers 1 and 2, the H

10 knives 3 in the grooves 6 while passing the H

nip from rollers 1 and 2. The push-back ribs come H

between the rollers 1 and 2 and the fiber 7 clamps

against the peripheral surface of counter-pressure roller 2b I

spot of profile 13. H

Figure 1 shows the fiber 7 which from top to bottom H

is fed between the rollers 1 and 2. The fiber 7 becomes I

clamped in the nip of rollers 1 and 2 between I

back ribs 4 and profiling 13 and is fixed by the H

blades 3 pushed into grooves 6, fiber 7 breaking, I

20 or is cut so that pieces of fiber 8 are pinched I

leave. I

From the part in the nip of figure 1 you can see how H

the convex profiles 13 depress the ribs 4, of which H

The walls 11 must be able to bend easily. The I

profiles 13 are shaped such that they on the one hand are

produce relatively concentrated impression, which I

prevents the ribs 4 from being pressed laterally

direction towards the blades, and on the other hand the bending I

30 do not make the wall 11 too strong to prevent wear

limit. I

In this exemplary embodiment, the counter-pressure roller is 2 and I

the blades 3 made of steel and are the I

f ft o r o 4 I

I 8 I back pressure ribs 4 made of elastic plastic I or rubber. In order to prevent the walls 11 of ribs 4 from changing shape due to elongation as a result of applying pressure in the cavity 10, the walls 11 are provided with a flexible reinforcement 16 in the form of a fabric or mat which is flexible but does not stretch.

The back pressure ribs 4 can be depressed relatively deeply. This is necessary in order to be able to pass the nip between rollers 1 and 2 and to be able to already secure the fiber 7 against the roller 2 when the blades 3 enter the grooves 6. This moment is precisely recorded in I figure 1. To this end, profile 13 is arranged slightly more pre-eminently than the center between two grooves 6.

I 20 I 25 I 30 | 1 02 3 62 1!

Claims (16)

A method for cutting H fibers into pieces, wherein a fiber (7) is divided into pieces by pressing a knife (3) against the fiber (7) which is H over a groove (6) in an H counterpressure roller (2) is retained by H pressure ribs (4) against the counter pressure roller (2), H wherein the pressure ribs are placed between the knives (3) H 10 of the knife roller, characterized in that the pressure ribs (4) are provided with H cavities (10) sealed at the roll ends H and which can be filled from the outside with air or a gas whose pressure is adjustable H 15 via the core (14) and channels (15) of the H knife roller. H Method according to claim 1, characterized in that the back pressure rib (4) has a semi-circular cross-section. 3. Method as claimed in claim 1, wherein the counterpressure roller (2) is provided with convex H profiles (13) which lie in substantially axial H direction between grooves (6) along the length of the counterpressure roller (2), such that co-operate with the back pressure ribs (4) that the H ribs do not expand sideways against the knives (3) and that stress concentrations are limited in the ribs (4) by pressing the profiles (13). I Method according to claim 1 or 2, characterized in that the walls (11) of the back pressure ribs (4) have a thickness of less than 1/10 of the distance between the knives (3) or the diameter of the rib (4) and that the wall I (11) is provided with a reinforcement (16) to prevent elongation, but does not obstruct that bending and which extends into the edges ( 12). Method according to one of claims 1, 2, 3 and 4, characterized in that the fiber to be cut (7) is bent during clamping between the rib (4) and profile (13), such that the mutual cohesion within fiber (7) is reduced and the cut fibers (8) easily fall apart after leaving the cutting device. 6. A method according to any one of claims 1-5, characterized in that the push-back rib (4) is roughened on the outer circumference by providing it with random irregularities, or with ribs in a desired pattern. 7. Method as claimed in any of the claims 1-5, characterized in that the surface of the counter-pressure roller (2) is roughened by arranging I random irregularities or ridges or I recesses according to a certain I pattern at the location where the counter-pressure ribs (4) I touch the roller (2), or profile (13) is interrupted at certain places. A method according to any one of claims 1-7, wherein temperature-conditioned air I is used to fill and rinse the ribs (4) and thus the rollers (1) and (2) to I a certain desired bring temperature to, or maintain. H Device for cutting H fibers into pieces, wherein a fiber (7) is divided into pieces H by pressing a knife (3) against the fiber (7) which is H over a groove (6) in an H counterpressure roller ( 2) is retained by H 10 pressure ribs (4) against the counter pressure roller (2), H wherein the pressure ribs are placed between the knives (3) H of the knife roller, characterized in that the pressure ribs (4) are provided with H cavities ( 10) which are sealed at the roll ends H 15 and which can be filled from the outside with H air or a gas whose pressure is adjustable H via the. core (14) and channels (15) of the H knife roller. I Device according to claim 9, characterized in that the back pressure rib (4) has a semi-circular cross-section. I 11. Device as claimed in claim 9, wherein the counterpressure roller (2) is provided with convex I profiles (13) which lie in substantially axial direction between grooves (6) along the length of the counterpressure roller (2), which cooperate in such a way with the pressure ribs (4) that the ribs do not expand sideways when pressed against the knives (3) and that stress concentrations are limited in the ribs (4) by pressing the profiles (13). I 1 n 9 * fi 9 Λ t_ I I 12 Device according to claim 9 or 10, characterized in that the walls (11) of the back pressure ribs (4) have a thickness that is less than 1/10 of the distance between the knives (3) or the diameter of the rib (4) and that the wall I (11) is provided with a reinforcement (16) to prevent elongation, but does not obstruct that bending and which extends into the edges (12). I 10 Device as claimed in any of the claims 9,10,11 and I 12, characterized in that the fiber to be cut (7) is bent during clamping between the rib (4) and I profile (13) such that the The mutual cohesion within fiber (7) is reduced and the cut fibers (8) easily fall apart after leaving the cutting device. Device according to any one of claims 9-13, characterized in that the push-back rib (4) is roughened on the outer circumference by providing it with random irregularities, or with ribs in a desired pattern. I - - / 1 I 25 15. Device as claimed in any of the claims 9-13, characterized in that the surface of the counterpressure roller (2) is roughened by arranging arbitrary irregularities or ridges or recesses according to a specific pattern at the location where the counter-pressure ribs (4) I touch the roller (2) or profile (13) is interrupted in certain places. | 1 02 3 62 1_ Device as claimed in any of the claims 9-15, H wherein use is made of temperature-conditioned air H to fill and rinse the ribs (4) and thereby the rollers (1) and (2) at a determined desired bring temperature to, or maintain. H 1 0 2 Λ fi? 1 I