APPARATUS, SYSTEM, AND METHOD FOR SPLICING CARBON FIBER TOW

Abstract

An entanglement apparatus includes a controller and a nozzle rotatably mounted for rotation about a nozzle axis. An entanglement section is coupled to a fluid supply and defines openings positionable to face overlapped ends of the fiber tows. At least one of the openings extends along an angled direction relative to the nozzle axis to create adjacent or overlapping fluid distribution paths, and two or more of which are disposed in irregular intervals along the entanglement section and relative to another two or more of the paths. The controller regulates a preselected property of the fluid supply, including a rotation characteristic of the nozzle to randomize the paths. The apparatus directs the fluid through the openings and along the paths toward the overlapped ends of the fiber tows while the nozzle is rotating about the nozzle axis and while the fiber tows, other than their overlapped ends, are maintained stationary.

Claims

1. An entanglement apparatus configured for entangling overlapped ends of fiber tows, the apparatus comprising: a nozzle rotatably mounted for rotation about a nozzle axis, the nozzle comprising an entanglement section defining openings positionable to face the overlapped ends of the fiber tows, the entanglement section being configured to be coupled to a fluid supply for receiving a fluid, wherein at least one of the openings extends along a direction at an angle relative to the nozzle axis such that the openings are configured to create adjacent or overlapping fluid distribution paths, and wherein two or more of the adjacent or overlapping fluid distribution paths are disposed in irregular intervals along the entanglement section and relative to another two or more of the adjacent or overlapping fluid distribution paths; and a controller configured to regulate a preselected property of the fluid supply, the preselected property of the fluid supply determining a rotation characteristic of the nozzle to randomize the adjacent or overlapping fluid distribution paths; wherein the entanglement apparatus is configured to direct the fluid through the openings and along the adjacent or overlapping fluid distribution paths toward the overlapped ends of the fiber tows while the nozzle is rotating about the nozzle axis and while the fiber tows, other than their overlapped ends, are maintained stationary.

2. The entanglement apparatus of claim 1, wherein the nozzle comprises a first nozzle and a second nozzle, the second nozzle being spaced apart from the first nozzle along the nozzle axis and oriented opposite of the first nozzle.

3. The entanglement apparatus of claim 1, wherein the entanglement section comprises an upstream area and a downstream area, and the openings comprise upstream openings disposed in the upstream area of the entanglement section and downstream openings disposed in the downstream area of the entanglement section.

4. The entanglement apparatus of claim 1, further comprising a gear assembly comprising at least one wheel configured to rotate about the nozzle axis.

5. The entanglement apparatus of claim 4, wherein the nozzle is rotatably mounted to the at least one wheel.

6. The entanglement apparatus of claim 5, wherein the nozzle is configured to rotate about the nozzle axis in response to rotation of the at least one wheel.

7. The entanglement apparatus of claim 4, wherein a first end section of the nozzle is rotatably mounted to a first wheel.

8. The entanglement apparatus of claim 7, wherein a second end section of the nozzle is rotatably mounted to a second wheel, and the second end section of the nozzle is opposite the first end section of the nozzle.

9. The entanglement apparatus of claim 7, wherein the first wheel is coupled to a first joint for delivering a first fluid stream supply to the nozzle.

10. The entanglement apparatus of claim 8, wherein the second wheel is coupled to a second joint for delivering a second fluid stream supply to the nozzle.

11. The entanglement apparatus of claim 4, further comprising a motor configured to cause rotation of the wheel of the gear assembly.

12. The entanglement apparatus of claim 11, wherein the gear assembly is coupled directly or indirectly to the motor.

13. The entanglement apparatus of claim 11, wherein the motor is a pneumatic motor.

14. The entanglement apparatus of claim 11, wherein the at least one wheel is configured to rotate about a wheel axis in response to activation of the motor.

15. The entanglement apparatus of claim 11, the gear assembly further comprising at least one gear interposed between the at least one wheel and the motor, the at least one gear being configured to be driven by the motor.

16. The entanglement apparatus of claim 1, wherein the rotation characteristic of the nozzle comprises a predetermined range of rotational speed.

17. The entanglement apparatus of claim 13, wherein the preselected property of the fluid supply comprises a predetermined range of air pressure supplied to an inlet of the pneumatic motor.

18. The entanglement apparatus of claim 1, wherein the openings include at least a first opening having a first diameter, and at least a second opening having a second diameter, the first diameter being different from the second diameter.

19. The entanglement apparatus of claim 1, wherein the apparatus is configured to produce fiber tows comprising: a first carbon fiber tow having a terminal end and a starting end; a second carbon fiber tow having a terminal end and a starting end; and a splice joint comprising joined portions of the first carbon fiber tow and the second carbon fiber tow; wherein the density of the spliced carbon fiber tow is substantially increased from the starting end of the first carbon fiber tow to the terminal end of the second carbon fiber tow.

20. The entanglement apparatus of claim 19, wherein the first and second carbon fiber tows are each made up of about 50,000 or more filament fibers.

21. The entanglement apparatus of claim 19, wherein a dry splice joint is able to withstand a tension force of at least 40 kg.

22. The entanglement apparatus of claim 19, wherein a dry splice joint is able to withstand a tension force of at least 60 kg.

23. The entanglement apparatus of claim 19, wherein the splice joint, impregnated with uncured epoxy resin, is able to withstand a tension force of at least 28 kg.

24. The entanglement apparatus of claim 19, wherein the splice joint, impregnated with uncured epoxy resin, is able to withstand a tension force of at least 50 kg.

25.-37. (canceled)

38. A system for entangling overlapped ends of fiber tows to form spliced carbon fiber tows, the system comprising: the entanglement apparatus of claim 1; and a source for delivering the fiber tows to the entanglement apparatus.

39. The system of claim 38, the source comprising a creel containing the fiber tows including a first reel having a coiled portion of a first carbon fiber tow and a second reel having a coiled portion of a second carbon fiber tow.

40. The system of claim 39, wherein the entanglement apparatus is mounted to an assembly moveable to one or more positions for operative engagement with the creel.

41. The system of claim 39, wherein the first and second carbon fiber tows are each made up of about 50,000 or more filament fibers.

42. The system of claim 41, wherein a dry splice joint of the fiber tows is able to withstand a tension force of at least 40 kg.

43. The system of claim 41, wherein a dry splice joint of the fiber tows is able to withstand a tension force of at least 60 kg.

44. The system of claim 41, wherein a splice joint of the fiber tows, impregnated with uncured epoxy resin, is able to withstand a tension force of at least 28 kg.

45. The system of claim 41, wherein a splice joint of the fiber tows, impregnated with uncured epoxy resin, is able to withstand a tension force of at least 50 kg.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The above and other aspects and features of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0008] FIG. 1 depicts a schematic of a system for entangling overlapped ends of fiber tows to form spliced carbon fiber tows in accordance with an embodiment of the invention;

[0009] FIGS. 2A-2B depict an entanglement apparatus configured for entangling overlapped ends of fiber tow in accordance with an embodiment of the invention;

[0010] FIG. 3A depicts an exploded view of the entanglement apparatus of FIG. 2A;

[0011] FIG. 3B depicts a section view of a portion of the entanglement apparatus of FIG. 3A;

[0012] FIG. 3C depicts a section view of another portion of the entanglement apparatus 35 of FIG. 3A;

[0013] FIGS. 4A-4F depict an entanglement apparatus configured for entangling overlapped ends of fiber tow in accordance with an embodiment of the invention, showing an exemplary carriage and exemplary carbon fiber tows;

[0014] FIG. 5 depicts a cross-section view of an exemplary air splicer puck of the entanglement apparatus of FIG. 2A; and

[0015] FIG. 6 depicts an exemplary method for entangling overlapped ends of fiber tows to form a spliced carbon fiber tow.

DETAILED DESCRIPTION OF THE INVENTION

[0016] The exemplary apparatus, method, and system disclosed herein are configured for configured for entangling overlapped ends of carbon fiber tows. In an exemplary embodiment, the carbon fiber tows are each made up of about 1 to 150,000 filament fibers, and each filament diameter is in a range of 4 to 14 microns.

[0017] In some instances, fiber ends can be spliced by applying a coating composition onto the fiber ends, placing the coated ends in contact, and drying or curing the coating to form a bonded splice. Such methods can be beneficial but may have disadvantages in some circumstances. For example, during subsequent manufacturing operations, the bonded area may not be compatible with the resin used to impregnate the fibers, which could also cause a local potential failure or premature failure.

[0018] Joining the ends of fibers from lengths of tow or yarn by air entanglement can be beneficial. In such methods, the ends of the tow or yarn are overlapped with each other and an air stream is applied to the overlapped portions to cause the fibers therein to become entangled with each other. Air entanglement can be comprised of steps such as: (1) rarefying fibers (optional in some cases); (2) lapping fibers head to tail; (3) blowing air through the nozzles; (4) reciprocating the tows in the nozzle; and (5) trimming excess fiber tails.

[0019] In some instances, the fiber density at the joined portion can become much greater than the fiber density in the main portions of the tow. In other words, the fiber density can be double in the splice area. In some cases, this increased bulk can damage part of the tow and may cause problems in subsequent operations. For example, in pultrusion processes, the increased bulk may have difficulty passing through the die and/or cause the resin impregnated therein not to fully penetrate the tow or not to cure completely.

[0020] An exemplary embodiment of a system for entangling overlapped ends of fiber tows to form spliced carbon fiber tows incorporating aspects of the present invention is disclosed in FIG. 1. In an exemplary embodiment, the system 1000 includes an entanglement apparatus 100 and a source 1100 for delivering the fiber tows to the entanglement apparatus 100. Additional details of entanglement apparatus 100 will be discussed further below. The source 1100 may include a creel 1100 containing the fiber tows including a first reel 1100a having a coiled portion of a first carbon fiber tow and a second reel 1100b having a coiled portion of a second carbon fiber tow. The entanglement apparatus 100 can be mounted to an assembly 1200 moveable to one or more positions for operative engagement with the creel 1100.

[0021] In one non-limiting example, the first and second carbon fiber tows are each made up of about 50,000 or more filament fibers. Additionally or optionally, a dry splice joint of the fiber tows is able to withstand a tension force of at least 40 kg. Alternatively, a dry splice joint of the fiber tows is able to withstand a tension force of at least 60 kg. Additionally or optionally, a splice joint of the fiber tows, impregnated with uncured epoxy resin, is able to withstand a tension force of at least 28 kg. Alternatively, a splice joint of the fiber tows, impregnated with uncured epoxy resin, is able to withstand a tension force of at least 50 kg.

[0022] Physical characteristics of the carbon fiber tows, including the density and tension force withstood by a (dry) splice joint of the fiber tows, are achieved via apparatus, methods, and systems for manufacturing spliced lengths of carbon fiber tows, as described in U.S. Pat. No. 9,193,559, assigned to the same assignee as the present application, which is incorporated by reference herein for all purposes.

[0023] Turning now to FIGS. 2A-2B and FIGS. 3A-3C, an entanglement apparatus 100 (such as the entanglement apparatus 100 of system 1000) is configured for entangling overlapped ends of fiber tow, e.g. carbon fiber tow 150. In an exemplary embodiment, one or more components of the apparatus 100 is partially or entirely housed within an enclosure. The enclosure may comprise a top housing portion 300, bottom housing 310, and a middle housing portion 320, which may be integrally formed as a unitary body or may be fastened to each other via known attachment means.

[0024] In general, the entanglement apparatus 100 includes a nozzle 110 and a controller 120 (FIG. 3A) in communication to one or more components of the apparatus 100, such as the nozzle 110 (as shown in FIG. 3A). The controller 120 is operatively coupled to the apparatus 100 for automatically controlling the operating sequence of the individual components and procedures. The nozzle 110 is rotatably mounted for rotation about a nozzle axis (A) (see FIG. 3C). In one non-limiting example, the nozzle 110 comprises a first nozzle 110a and a second nozzle 110b, with the second nozzle 110b being spaced apart from the first nozzle 110a along the nozzle axis (A) and oriented opposite of the first nozzle (see FIGS. 4A-4B).

[0025] In an exemplary embodiment, the nozzle 110 comprises an air splicing puck 112. In another embodiment, a first air splicing puck 112a and a second air splicing puck 112b may be oriented opposite of the first air splicing puck 112a (see FIGS. 4B and 5). Each of the air splicing pucks 112 comprises an entanglement section 130 (FIG. 5) defining a plurality of openings 132. The openings 132 are positionable to face the overlapped ends of the fiber tows (as best shown in FIGS. 4A-4B). In a non-limiting example, at least one of the openings 132 extends along a direction at an angle relative to the nozzle axis (A), such that the openings 132 are configured to create adjacent or overlapping fluid distribution paths defined by the openings 132. In this way, a plurality of the openings 132 extends along a plurality of angled directions, thereby creating multiple sets or pairs of adjacent or overlapping fluid distribution paths.

[0026] Additionally or optionally, two or more of the adjacent or overlapping fluid distribution paths are disposed in irregular intervals along the entanglement section and relative to another two or more of the adjacent or overlapping fluid distribution paths. It should be understood the number of, angled directions, and position of the openings 132 as illustrated in FIG. 5 are not intended to be limiting, but rather the number, angled directions, position, and/or other characteristics of the openings 132 20) relative to one another or to another set of openings 132 may be varied from that specifically illustrated in FIG. 5 without departing from the spirit of the invention. For example, as illustrated in FIG. 5, the entanglement section 130 includes an upstream area and a downstream area, and the openings comprise upstream openings 132a disposed in the upstream area of the entanglement section 130 (e.g. for facilitating a fluid connection between a fluid supply 140 (discussed below)) and downstream openings 132b disposed in the downstream area of the entanglement section 130 (e.g. for facilitating another fluid connection between the nozzle 110/air splice puck 112 and the fiber tows 150.). Additionally or optionally, the openings 130 include at least a first opening 132a having a first diameter, and at least a second opening 132b having a second diameter, the first diameter being different from the second diameter.

[0027] The entanglement section 130 is configured to be coupled to the fluid supply 140 for receiving a fluid (e.g. air). In an exemplary embodiment, the fluid supply 140 is coupled to the entanglement section 130 via a rotating joint 160 coupled to one or more components of the apparatus 100. Rotating joint 160 may be coupled to one or more components of apparatus 100 via rotary joint clamp(s) 162. As shown in FIGS. 3A-3C, a rotating joint 160 to which the fluid supply 140 may be connected is positioned above and below the nozzle 110.

[0028] The controller 120 is configured to regulate a preselected property of the fluid supply 140. In an exemplary embodiment, the preselected property of the fluid supply 140 includes determining a rotation characteristic of the nozzle 110 to randomize the adjacent or overlapping fluid distribution paths defined by the openings 132. In an exemplary embodiment, the rotation characteristic of the nozzle 110 comprises a predetermined range of rotational speed. Additionally or optionally, the preselected property of the fluid supply 140 comprises a predetermined range of air pressure supplied to an inlet of the pneumatic motor.

[0029] The apparatus 100 is configured to direct the fluid through the openings 132 and along the adjacent or overlapping fluid distribution paths defined by the openings 132 toward the overlapped ends of the fiber tows while the nozzle 110 is rotating about the nozzle axis (A) and while the fiber tows 150, other than their overlapped ends 150a, are maintained stationary (see FIGS. 4C-4F). To facilitate the rotation of the nozzle 110 and direction of the fluid through the openings 132, the nozzle 110 is rotatably mounted to at least one wheel 180 (FIG. 3B) that is configured to rotate about the nozzle axis (A), such that the nozzle 110 is configured to rotate about the nozzle axis (A) in response to rotation of the at least one wheel 180.

[0030] In an exemplary embodiment, a first end section of the nozzle 110 is rotatably mounted to a first wheel. Additionally or optionally, a second end section of the nozzle 110 is rotatably mounted to a second wheel, and the second end section of the nozzle 110 is opposite the first end section of the nozzle. The first wheel is coupled to a first joint, such as rotating joint 160, for delivering a first fluid stream supply to the nozzle 110. The second wheel is coupled to a second joint, such as another rotating joint 160, for delivering a second fluid stream supply to the nozzle 110.

[0031] Rotation of the wheel 180 is facilitated by a gear assembly and a motor directly or indirectly connected to the gear assembly. In an exemplary embodiment, the motor is a pneumatic motor. In a non-limiting example, as shown in FIG. 3B, the gear assembly comprises at least one metal gear 174, at least one ball bearing 170, and a dowel pin 172 extending through respective apertures defined by the at least one ball bearing 170 and at least one metal gear 174. Shims 176 may be disposed between the at least one ball bearing 170 and the at least one metal gear 174. Rotation of the at least one gear 174 when the motor is activated causes rotation of the wheel 180 about the wheel axis (co-located with the nozzle axis (A)), which causes the nozzle 110 to rotate about the nozzle axis (A). In other words, the gear assembly can include at least one gear 174 interposed between the at least one wheel 180 and the motor, and the at least one gear 174 is configured to be driven by the motor.

[0032] In operation, the entanglement apparatus 100 is configured to produce fiber tows having one or more of the following characteristics: a first carbon fiber tow having a terminal end and a starting end; a second carbon fiber tow having, a terminal end and a starting end; and a splice joint comprising joined portions of the first carbon fiber tow and the second carbon fiber tow. The density of the spliced carbon fiber tow is substantially increased from the starting end of the first carbon fiber tow to the terminal end of the second carbon fiber tow. Optionally, the first carbon fiber two has a rarefied portion extending from the terminal end to a first joint end and/or the second carbon fiber two having a rarefied portion extending from the starting end to a second joint end. In this way, the splice joint comprises joined rarefied portions of the first carbon fiber two and the second carbon fiber tow. This is achieved at least via apparatus, methods, and/or systems for manufacturing spliced lengths of carbon fiber tows.

[0033] A method 2000 for entangling overlapped ends of fiber tows to form a spliced carbon fiber tow is disclosed and will be described in the context of apparatus 100 and system 1000 discussed above. Turning to FIGS. 4C-4F and 6, the fiber tows 150 include a first carbon fiber tow having a terminal end and a starting end and a second carbon fiber tow having a terminal end and a starting end.

[0034] In step 2100, a region of the first carbon fiber tow is aligned with a region of the second carbon fiber tow to form overlapped ends 150a of the fiber tows 150 (as shown in FIGS. 4C and 4E). The overlapped ends 150a may be partially (FIG. 4C) or entirely (FIG. 4E) overlapped relative to each other.

[0035] In step 2200, a nozzle 110 is rotated about a nozzle axis (A).

[0036] In step 2300, a fluid stream from a fluid supply 140 is directed, through openings 132 defined in an entanglement section 130 of the nozzle 110 having openings 132 facing the overlapped ends 150a of the fiber tows 150, and toward the overlapped ends 150a of the fiber tows 150 at an angle relative to the nozzle axis (A) to create adjacent or overlapping fluid distribution paths defined by the openings 132. In step 2400, the fiber tows 150 other than their overlapped ends 150a are maintained as stationary.

[0037] In step 2500, the rotation characteristic of the nozzle 110 is maintained (e.g. by controller 120) based on a preselected property of the fluid supply 140.

[0038] Additionally or optionally, method 2000 includes a step of forming the first and second carbon fiber tows to include about 50,000 or more filament fibers. Still further, method 2000 includes cutting and removing a portion of the fiber filaments of the first carbon fiber tow (optionally, a rarefied region that extends from the terminal end of the first carbon fiber tow to a first joint end is formed) as shown in FIGS. 4C and 4E. Moreover, method 2000 includes a step of cutting and removing a portion of the fiber filaments of the second carbon fiber tow (optionally, a rarefied region that extends from the starting end of the second carbon fiber tow to a second joint end is formed). Method 2000 also has a step of positioning the starting end of the second carbon fiber tow to meet the first joint end of the first carbon fiber tow, and positioning the terminal end of the first carbon fiber tow to meet the second joint end of the second carbon fiber tow. In this way, the overlapped ends 150a of the plurality of fiber tows comprise the first joint end and the second joint end. Further, method 2000 includes forming a splice joint comprising joined rarified portions of the first carbon fiber tow and the second carbon fiber tow.

[0039] In an exemplary embodiment of the method 2000, a density of the spliced carbon fiber tow is substantially uniform from the starting end of the first carbon fiber tow to the terminal end of the second carbon fiber tow. This is achieved at least via apparatus, methods, and/or systems for manufacturing spliced lengths of carbon fiber tows, as disclosed in the '559 patent described above. For example, method 2000 includes a step of forming the first and second carbon fiber tows from about 50,000 or more filament fibers. Additionally or optionally, method 200 includes configuring a dry splice joint to withstand a tension force of at least 40 kg or at least 60 kg. Additionally or optionally, method 200 includes configuring the splice joint, impregnated with uncured epoxy resin, to withstand a tension force of at least 28 kg or at least 50 kg.

Examples

[0040] As detailed in the '559 patent, two lengths of Panex 35 carbon fiber tow, having 50,000 fibers each were spliced by overlapping the ends and subjecting the ends to air entanglement. The tensile strength of the Panex 35 carbon fiber tow used was about 4137 Mpa, the tensile modulus was about 242 GPa, and the density was about 1.81 g/cc. The fiber diameter of the fibers of the tow was about 7.2 microns. The density of the spliced carbon fiber tow is substantially uniform along the length of the tow. The strength of the splice of the resulting spliced carbon fiber tow as tested by measuring the force required to split the splice. Table 1 below lists the splice strength for a number of tested splices.

TABLE-US-00001 TABLE 1 Standard PX-35, 2 50K splice split Test lbs newtons 1 91.2 405.66 2 52.6 233.96 3 71.2 316.70 4 84.8 377.19 5 85.4 379.86 6 106.6 474.16 7 43.8 194.82 8 117.4 522.20 9 86.4 384.31 10 68.4 304.24 11 93.4 415.44 12 114.6 509.74 13 87.8 390.53 14 88.8 394.98 15 72.9 324.26

[0041] As shown in Table 1 above, the ranges of splice strength of fiber tows produced by apparatuses, methods, and systems disclosed herein is at least 45 lbs, preferably 50 lbs or more, more preferably 60 lbs or more, and even more preferably 70 lbs or more.

[0042] While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. For example, the splices described herein may be used for any application where tow splicing is needed, and are not limited to pultrusion. Additionally, variations, changes and substitutions among the different embodiments discussed above may fall within the spirit and scope of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.