Abstract
A card clothing wire is disclosed, especially for a doffer or a worker of a carding machine, which provides a superior retention of fibers during a carding process and which can be universally used to produce nonwoven webs with an increased grammage or to produce nonwoven webs with a low grammage and an increased quality. In one form, the card clothing wire includes a tooth depth of less than 1.7 mm and an overhanging tip with an undercut.
Claims
1. A card clothing wire (1) for a doffer (20), a worker (21), or a stripper (25) of a carding machine (18), the card clothing wire comprising: a rib portion which extends in a longitudinal direction (L) of the card clothing wire (1); a plurality of teeth (2) which are arranged side by side in the longitudinal direction (L) on the rib portion (17); wherein at least one tooth (2) of the plurality of teeth is bounded by a tooth-back (3) on a first side in the longitudinal direction (L); wherein the at least one tooth (2) is bounded by a tooth-breast (4) on a second side in the longitudinal direction (L), a tip (5) is formed between the tooth-back (3) and the tooth-breast (4) at a highest point of the tooth (2) in a height direction (H), wherein the height direction (H) is perpendicular to the longitudinal direction (L); an edge-face (6) of the tooth-breast (4) that abuts the tip (5); an undercut (7) is arranged on the tooth-breast (4) underneath the edge-face (6) in the height direction, wherein the undercut (7) abuts the edge-face (6) and extends towards the tooth-back (3) relative to the edge-face (6); a tip angle (15) formed between a tangent of the edge-face (6) and the longitudinal direction (L); and an undercut angle (16) formed between a tangent of the undercut (7) and the longitudinal direction (L); wherein the undercut angle (16) is smaller than the tip angle (15); a tooth-root (8) which connects the tooth-breast (4) and the tooth-back (3) of adjacent teeth (2) of the plurality of teeth (2) at their lowest point in the height direction (H); wherein a tooth depth (9) measured in the height direction (H) between the tip (5) and a lowest point of the tooth-root (8) is smaller than 1.7 mm.
2. The card clothing wire (1) according to claim 1, wherein the at least one tooth (2) has a wire height (10) of less than 3 mm, wherein the wire height (10) is measured in the height direction (H) between the tip (5) and the lowest point of the rib portion (17).
3. The card clothing wire (1) according to claim 1, wherein a front angle (11) measured between a tangent of the tooth-breast (4) and the longitudinal direction (L) is from 450 to 65.
4. The card clothing wire (1) according to claim 1, wherein the undercut (7) comprises a linear portion (12) which is parallel to the longitudinal direction (L).
5. The card clothing wire (1) according to claim 1, wherein a curved portion (13) of the tooth-breast (4) abuts the undercut (7) at an end of the undercut (7) which is spaced apart from the edge-face (6), wherein the curved portion has a constant radius of curvature (R).
6. The card clothing wire (1) according to claim 1, wherein a back angle (14) measured between a tangent of the tooth-back (3) and the longitudinal direction (L) is less than the undercut angle (16).
7. The card clothing wire (1) according to claim 1, wherein the tooth-breast (4) comprises at least two undercuts (7).
8. A carding machine (18) comprising the card clothing wire of claim 1, the carding machine comprising: a main cylinder (19); and at least one of: a doffer (20), a worker (21) and a stripper (25) comprising the card clothing wire (1).
9. The carding machine (18) according to claim 8, wherein the main cylinder (19) comprises a tooth population of 270 to 550 points per square inch (ppsi).
10. The carding machine (18) according to claim 8, wherein the doffer (20) comprises a tooth population of 230 to 460 points per square inch (ppsi).
11. The carding machine (18) according to claim 8, wherein: the main cylinder (19) comprises a card clothing wire having a tooth depth (9) of at least 0.7 mm.
12. A carding process for producing a nonwoven using the card clothing wire (1) of claim 1, the process comprising: transferring fibers from a main cylinder (19) to at least one of a doffer (20), a worker (21), and a stripper (25) comprising the card clothing wire (1) to produce a nonwoven web wherein the fibers are transferred from the main cylinder (19) to the at least one of a doffer (20), a worker (21), and a stripper (25) comprising the card clothing wire by the teeth (2) of the card clothing wire (1) which have a tooth depth (9) of less than 1.7 mm.
13. The carding process according to claim 12, wherein transferring fibers from the main cylinder (19) to the at least one of a doffer (20), a worker (21), and a stripper (25) comprising the card clothing wire (1) produces a nonwoven with a grammage of less than 5 gsm (grams per square meter).
14. The carding process according to claim 12, wherein a grammage of the produced nonwoven web is increased by decreasing the tooth depth (9) of the card clothing wire (1) of the doffer (20).
15. The carding process according to claim 12, wherein the fibers are transferred from the main cylinder (19) to the doffer (20) and the fibers comprise at least one of glass fibers, carbon fibers, static charged fibers, and hybrid fibers, wherein the hybrid fibers comprise at least two different materials.
16. The card clothing wire of claim 1, wherein the tooth depth (9) is smaller than 1.5 mm.
17. The carding machine (18) of claim 11, wherein the card clothing wire has a tooth depth (9) of at least 0.8 mm.
18. The carding process of claim 12, wherein the teeth (2) of the card clothing wire (1) have a tooth depth (9) of less than 1.5 mm.
19. The carding process of claim 13, wherein transferring fibers from the main cylinder (19) to the at least one of a doffer (20), a worker (21), and a stripper (25) comprising the card clothing wire (1) produces a nonwoven with a grammage of less than 4 gsm (grams per square meter).
Description
[0032] FIG. 1 shows a first embodiment of a card clothing wire (1).
[0033] FIG. 2 shows a carding machine (18) and the transfer path (22) of fibers in this carding machine (18).
[0034] FIG. 3 shows a second embodiment of a card clothing wire (1).
[0035] FIG. 4 shows a third embodiment of a card clothing wire (1).
[0036] FIG. 1 shows a first embodiment of a card clothing wire 1. The card clothing wire 1 comprises teeth 2 which are longitudinally arranged side by side on a rib portion 17 which extends in a longitudinal direction L of the card clothing wire 1. In FIG. 1 only a section of the card clothing wire 1 with one tooth 2 is shown. The tooth 2 is bounded by a tooth-back 3 on a first side and a tooth-breast 4 on a second side in the longitudinal direction L. A tip 5 is formed between the tooth-back 3 and the tooth-breast 4 at the highest point of the tooth 2 in a height direction H which is perpendicular to the longitudinal direction L. Such card clothing wires are circumferentially wound around the rollers (e.g. main cylinder, doffer, worker) of a carding machine during a carding-process. Due to a rotational movement of these rollers the teeth 2 of the card clothing wire 2 are moved in a circumferential direction of the rollers to grip fibers during the carding-process. Thereby, the tooth-breast 4 is in a functional contact with the fibers to retain them on the teeth 2. A tangent of the tooth-breast 4 is arranged in an angle to the longitudinal direction which is defined as the front angle 11. The front angle 11 preferably is 25 degrees to 45 degrees. To improve the retention of the fibers, the tooth-breast 4 comprises an edge-face 6 which abuts on the tip 5 and an undercut 7 which abuts on the edge-face 6. The undercut 7 is spaced apart from the tip 5 and extends relatively to the edge-face 6 towards the tooth-back 3. The card clothing wire 1 furthermore comprises two additional undercuts 7. Each additional undercut 7 further increases the retention of fibers at the teeth 2. The edge-face 6 and the undercuts 7 are arranged in different angles to the longitudinal direction L. The angle of the edge-face 6 hereafter is referred to as tip angle 15, whereas the angle of the undercuts 7 is referred to as undercut angle 16. To form an overhanging tip the undercut angle 16 is smaller than the tip angle 15. The undercuts 7 of the first embodiment of the card clothing wire 1 shown in FIG. 1 comprises linear portions 12 with an undercut angle 16 of zero degrees, which means the linear portions 12 are substantially parallel to the longitudinal direction L. Thus, the retention of fibers at the undercuts 7 is improved. Subsequent teeth 2 of the card clothing wire 1 are connected with each other at their lowest point referring to the height direction H by a tooth-root 8. The distance in the height direction H between the tooth-root 8 and the tip 5 is defined as the tooth depth 9. In a preferred embodiment of the invention the tooth depth 9 is smaller than 1.7 mm but preferably smaller than 1.5 mm. Experiments, which were conducted by the applicant, surprisingly showed that the grammage of a nonwoven web produced with such a card clothing wire on a doffer of a carding machine can be increased. The total height of the card clothing wire is called wire height 10 and can be defined as the sum of the tooth depth 9 and the height of the rib portion 17. In a preferred embodiment of the invention the wire height is less than 3 mm.
[0037] FIG. 2 shows a schematic view of a carding machine 18 and the transfer path 22 on which fibers are transported in such a carding machine 18 during a carding-process. Only the main cylinder 19, a worker 21, a doffer 20, a stripper 25 and a licker-in 24 which are rollers or cylinders of the carding machine 18 are shown. Each of them is equipped with a card clothing wire. Advantageously, at least the doffer 20 and/or the worker 21 are equipped with a card clothing wire 1 shown in FIG. 1. A main cylinder with a tooth population of 270 to 470 ppsi and/or a doffer 20 with a tooth population of 250 to 370 ppsi can contribute to further improvements. In a preferred embodiment the main cylinder 19 comprises a card clothing wire 1 with a tooth depth 9 of at least 0.85 mm to process fibers efficiently. When glass fibers, carbon fibers, static charged fibers or hybrid fibers are processed, the fibers usually tend to wrap around the teeth 2 of the card clothing wire 1 of the doffer 20 and thus clog the doffer 20. A carding machine 18 with the aforementioned properties avoids this effect. Typically, carding machines 18 can comprise further machine parts which are not shown in this figure because these machine parts are unnecessary to define and understand the subject matter claimed with this patent application. A description of how fibers are transferred in the carding machine 18 follows: the transfer path 22 is the path on which fibers are transported in a carding machine. The transfer direction 23, in which the fibers are transported on the transfer path 22, is shown with an arrow at the end of the transfer path 22. In the carding machine 18 fiber tufts are fed towards a licker-in 24 and get gripped by the teeth 2 of the card clothing wire which is wound around the licker-in 24. The licker-in 24 transports the fiber tufts on a transfer path 22 in a circumferential direction of the licker-in 24 towards the main cylinder 19. At a point where the licker-in 24 is close to the main cylinder 19, the teeth 2 of the card clothing wire of the main cylinder 19 grip the fibers to transfer them from the licker-in 24 to the main cylinder 19. At this point the licker-in 24 and the main cylinder 19 both rotate in the same circumferential direction, which is indicated by the arrows shown in FIG. 2. A main function of the carding machine is to disentangle these fiber tufts into single fibers. The main cylinder 19 subsequently transports the fibers on the transfer path 22 in a circumferential direction of the main cylinder 19 towards one or more workers 21. In FIG. 2 only one worker 21 is shown. The worker 21 is arranged close to the main cylinder 19. At the nearest point of the circumferential surface of the worker 21 to the circumferential surface of the main cylinder 19 the worker 21 can grip fibers of a fiber tuft to disentangle the fiber tuft. The fibers gripped by the worker 21 are transferred to an accompanying stripper 25 which re-deposits the disentangled fibers back onto the main cylinder 19. Thus, fiber tufts get disentangled into single fibers. In practice, most fibers and fiber tufts stay on the main cylinder 19 for several revolutions and are thus recycled several times on the same worker 21 and stripper 25 to improve the disentanglement of the fibers. After disentangling the fiber tufts the main cylinder 19 transports the single fibers towards a doffer 20. At a point where the teeth 2 of the doffer 20 can grip the single fibers, the fibers are transferred to the doffer 20. At this point the doffer 20 condenses the fibers and combines them into a web because of its substantially lower peripheral speed relative to the main cylinder 19. The doffer 20 transports the web in a circumferential direction to a point where the web is drawn off from the doffer 20 for subsequent treatment.
[0038] FIG. 3 shows a section of a second embodiment of a card clothing wire 1 which is suitable to be used on a doffer 20 or a worker 21 of a carding machine 18. The card closing wire 1 comprises two teeth 2 arranged on a rib portion 17 in this section. The teeth 2 have the following properties in common with the tooth 2 shown in FIG. 1: [0039] a tooth-back 3, a tooth-breast 4, a tip 5, an edge-face 6, an undercut 7, a tooth-root 8 and an undercut angle 16 which is smaller than a tip angle 15.
Furthermore, the tooth-breast 4 of each of the teeth 2 comprises a curved portion 13 which abuts on an end of the undercut 7 which is spaced apart from the edge-face 6. The curved portion has a constant radius R. Thus, these teeth 2 offer an increased retention of fibers during the carding-process.
[0040] FIG. 4 shows a section of a third embodiment of a card clothing wire 1 which is suitable to be used on a doffer 20 or a worker 21 of a carding machine 18. The card closing wire 1 comprises two teeth 2 arranged on a rib portion 17 in this section. The teeth 2 have the following properties in common with the tooth 2 shown in FIG. 1: [0041] a tooth-back 3, a tooth-breast 4, a tip 5, an edge-face 6, an undercut 7, a tooth-root 8 and an undercut angle 16 smaller than a tip angle 15.
Furthermore, in this embodiment the back angle 14 which is the angle between a tangent of the tooth-back 3 and the longitudinal direction L is smaller than the undercut angle 16. Thus, the teeth 2 can be produced by rotary punching to reduce manufacturing costs.
TABLE-US-00002 List of numerals 1 Card clothing wire 2 Tooth 3 Tooth-back 4 Tooth-breast 5 Tip 6 Edge-face 7 Undercut 8 Tooth-root 9 Tooth depth 10 Wire height 11 Front angle 12 Linear portion 13 Curved portion 14 Back angle 15 Tip angle 16 Undercut angle 17 Rib portion 18 Carding machine 19 Main cylinder 20 Doffer 21 Worker 22 Transfer path of fibers 23 Direction of fiber transfer 24 Licker-in 25 Stripper L Longitudinal direction H Height direction R Radius of the curved section (13)
