Apparatus and method for separating reinforced fiber bundles

Abstract

To provide a dividing device of reinforced fiber bundles which can finely divide the reinforced fiber bundles and a dividing method of the reinforced fiber bundles which can finely divide the reinforced fiber bundles.SOLUTION: A dividing device 3 divides reinforced fiber bundles 50. The dividing device includes slit rollers 30, 31 which are rotatable from surfaces of the conveyed reinforced fiber bundles 50. The slit rollers 30, 31 advance / retreat with respect to the reinforced fiber bundles 50 so that the slit rollers can bite into the surfaces of the reinforced fiber bundles 50. A plurality of slit roller 30, 31 are provided. Advancing time timings of the plurality of slit rollers 30, 31 provided may be alternate so that advancing time timings overlap.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an apparatus for splitting a reinforcing fiber bundle and a method for splitting a reinforcing fiber bundle. [Background technology]

[0002] Conventionally, in order to increase the strength of a resin product, a technique for impregnating a resin sheet, which is a base material of the resin product, with reinforcing fibers during molding has already been known. As the reinforcing fibers to be impregnated, for example, manufacturers sell a high-fineness state in which multiple reinforcing fibers (for example, several thousand to tens of thousands) are bundled with a sizing agent, and it is said that the number of bundles is as small as possible to increase strength, but there is a disadvantage that the cost of the reinforcing fiber manufacturer increases. In order to achieve both strength and cost, it is necessary for the molding manufacturer to split the reinforcing fiber bundle to make it low fineness. For example, the technique of Patent Document 1 is known as a method for splitting the reinforcing fiber bundle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-213537 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology of Patent Document 1 mentioned above requires a large process to separate the reinforcing fiber bundles, and only reinforcing fiber bundles from which the sizing agent has been removed can be separated, and the cutter unit puts a strain on the raw yarn, making it prone to splitting.

[0005] The present invention has been made in consideration of the above circumstances, and the problem that the present invention aims to solve is to provide a reinforcing fiber bundle splitting device that can finely split reinforcing fiber bundles without removing not only the sizing agent but also the material impregnated with matrix resin, and without placing a burden on the reinforcing fiber bundles, and a reinforcing fiber bundle splitting method that can finely split reinforcing fiber bundles. [Means for solving the problem]

[0006] According to one feature of the present disclosure, a fiber splitting device for splitting a reinforcing fiber bundle includes a slit roller that can rotate from the surface of the reinforcing fiber bundle being conveyed. The slit roller advances and retreats relative to the reinforcing fiber bundle so as to be able to bite into the surface of the reinforcing fiber bundle.

[0007] Therefore, the tip of the slit roller can bite into the surface of the reinforcing fiber bundle being conveyed. Therefore, by repeating this biting of the slit roller, the reinforcing fiber bundle can be finely separated without removing not only the sizing agent but also the matrix resin impregnated material and without putting a burden on the reinforcing fiber bundle.

[0008] According to another feature of the present disclosure, a plurality of slit rollers are provided, and the timings of the advancement of the plurality of slit rollers are alternated so that the advancement timings overlap each other.

[0009] Therefore, for example, even when separating a reinforcing fiber bundle in which the bundled reinforcing fibers are not aligned in one direction (a reinforcing fiber bundle in which the reinforcing fibers partially cross), cutting or damage to the reinforcing fibers during the separation can be prevented.

[0010] According to another feature of the present disclosure, the upstream and downstream sides of the slit roller are provided with hold-down rollers for holding down the reinforcing fiber bundles. Here, "hold down" means "hold down with a single roller," "hold down by sandwiching between multiple rollers," "hold down with a flat surface on one side and a roller on the other side," etc.

[0011] Therefore, the flapping up and down of the reinforcing fiber bundles in the fiber splitting device can be suppressed.

[0012] According to another feature of the present disclosure, the slit roller is rotatable by a driving means.

[0013] Therefore, the tip of the slit roller can be reliably inserted into the surface of the reinforcing fiber bundle.

[0014] According to another feature of the present disclosure, a sensor capable of detecting a load acting on the slit roller from the reinforcing fiber bundle is provided. When the load detected by the sensor exceeds a predetermined threshold, the slit roller retracts from the reinforcing fiber bundle.

[0015] Therefore, breakage or tearing of the reinforcing fibers during splitting can be prevented.

[0016] According to another feature of the present disclosure, there is provided a method for splitting a reinforcing fiber bundle, in which a slit roller is rotated in a conveying direction while the slit roller is moved back and forth over the surface of the conveyed reinforcing fiber bundle to split the reinforcing fiber bundle.

[0017] Therefore, the tip of the slit roller can bite into the surface of the reinforcing fiber bundle being conveyed. Therefore, by repeating this biting of the slit roller, the reinforcing fiber bundle can be finely separated without removing not only the sizing agent but also the matrix resin impregnated material and without putting a burden on the reinforcing fiber bundle. [Brief description of the drawings]

[0018] [Figure 1] A schematic side view of a fiber splitting system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic plan view of a first slit roller in FIG. [Diagram 3] This is a schematic diagram explaining the operation of the fiber separating system of Figure 1. [Figure 4] FIG. 4 is a schematic diagram illustrating the next operation of FIG. 3. [Diagram 5]FIG. 5 is a schematic diagram illustrating the next operation of FIG. 4. [Figure 6] FIG. 6 is a schematic diagram illustrating the next operation of FIG. 5. [Figure 7] FIG. 7 is a schematic diagram for explaining the next operation of FIG. 6. [Figure 8] A schematic diagram explaining another operating pattern of the fiber separating system of Figure 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to Figures 1 to 7. First, a fiber splitting system 1 according to an embodiment of the present invention will be described (see Figure 1). This fiber splitting system 1 is for splitting a reinforcing fiber bundle 50 in which a plurality of reinforcing fibers (not shown) (e.g., several thousand to tens of thousands) are bundled by a sizing agent or matrix resin, and includes a fiber opening device 2, a fiber splitting device 3, and a feeding device 4. Below, the fiber opening device 2, the fiber splitting device 3, and the feeding device 4 will be described individually.

[0020] The reinforcing fibers referred to here are fibers such as carbon fibers, glass fibers, metal fibers, and ceramic fibers that are high in strength and generally serve the purpose of acting as a reinforcing material for resins, and the matrix resin refers to pre-cured thermoplastic resins such as thermoplastic resins represented by polyamide resin, polypropylene resin, polyetherimide resin, polyether ether ketone resin, and polyphenylene sulfide resin, as well as thermosetting resins represented by unsaturated polyester resin, epoxy resin, urethane resin, and acrylic resin. The sizing agent refers to materials generally used as sizing agents, such as acrylic pastes, waxes, and the same epoxy resins as the matrix resin.

[0021] First, a description will be given of the fiber-spreading device 2. The fiber-spreading device 2 includes a first roller 20 that supports from below the reinforced fiber bundle 50 transported from a transport device (not shown), a second roller 21 that is located downstream of the first roller 20 and supports the reinforced fiber bundle 50 from above, a third roller 22 that is located downstream of the second roller 21 and supports the reinforced fiber bundle 50 from below, and a fourth roller 23 that is located vertically opposite the third roller 22 and supports the reinforced fiber bundle 50 from above.

[0022] The fourth roller 23 holds down the reinforcing fiber bundle 50 from above. Therefore, the third roller 22 and the fourth roller 23 can sandwich the reinforcing fiber bundle 50 from above and below. The fourth roller 23 corresponds to a "holding roller" in the claims. The first roller 20, the second roller 21, and the third roller 22 are provided on the same line along the conveying direction of the reinforcing fiber bundle 50 (the direction of the arrow A in FIG. 1).

[0023] Next, the fiber splitting device 3 will be described. The fiber splitting device 3 is provided with a first slit roller 30 located downstream of the fiber spreading device 2 and supporting the spread reinforced fiber bundle 50 from above, and a second slit roller 31 located downstream of the first slit roller 30 and supporting the spread reinforced fiber bundle 50 from below. The first slit roller 30 is provided with a plurality of circular disk portions 30a, a plurality of circular spacers 30b, and a rotating shaft 30c, and is configured such that the spacer 30b, with which the rotating shaft 30c is concentric, is interposed between the plurality of disk portions 30a (see FIG. 2).

[0024] Similarly to the first slit roller 30, the second slit roller 31 also includes a plurality of disk portions 31a, a plurality of spacers 31b, and a rotating shaft 31c, and is configured such that the spacers 31b are interposed between the plurality of disk portions 31a and the rotating shaft 31c is concentric with the disk portions 31a. The first slit roller 30 and the second slit roller 31 are assembled so as to be rotatable in the conveying direction by frictional force against the surface of the conveyed reinforcing fiber bundle 50.

[0025] In addition, the first slit roller 30 and the second slit roller 31 are mechanically connected to a motor (not shown) which is a driving means. Therefore, the first slit roller 30 and the second slit roller 31 can also rotate (spin) by the motor drive. The rotation speed is a speed synchronized with the conveying speed of the conveyed reinforcing fiber bundle 50 or a speed faster than the conveying speed of the conveyed reinforcing fiber bundle 50.

[0026] This prevents the reinforcing fibers from being damaged. The direction of rotation is the forward direction of the conveyed reinforcing fiber bundle 50. The first slit roller 30 and the second slit roller 31 are mechanically connected to an elevator (not shown). Therefore, the first slit roller 30 and the second slit roller 31 can be raised and lowered (advanced and retreated) relative to the conveyed reinforcing fiber bundle 50.

[0027] Therefore, the first slit roller 30 and the second slit roller 31 are configured so that the tips of the disk portions 30a, 31a thereof can bite into the surface of the conveyed reinforced fiber bundle 50. The first slit roller 30 has an elevation angle θ1 (an elevation angle with respect to the conveying direction) of, for example, 90°. The second slit roller 31 has an elevation angle θ2 (an elevation angle with respect to the conveying direction) of, for example, 90°.

[0028] The fiber splitting device 3 also includes a sensor (not shown) capable of detecting the load acting on the first slit roller 30 and the second slit roller 31 from the reinforcing fiber bundle 50. When the load detected by this sensor exceeds a predetermined threshold, the first slit roller 30 rises from the reinforcing fiber bundle 50, and the second slit roller 31 descends from the reinforcing fiber bundle 50.

[0029] The "load" referred to here means that when the slit roller separates the reinforcing fiber bundle by rotating on its own or due to friction with the reinforcing fiber bundle, more resistance than necessary may be applied. For example, the reinforcing fiber bundle is an untwisted yarn, but there are places where the single yarns cross, and if the slit roller continues to separate the yarns as is, there is a possibility that the single yarns will split or be cut. When the load sensor detects this, the slit roller moves away from the reinforcing fiber bundle, preventing splitting and cuts without forcibly cutting.

[0030] Next, the feeding device 4 will be described. The feeding device 4 includes a first roller 40 located downstream of the fiber splitting device 3 and supporting the split reinforcing fiber bundle 50 from below, a second roller 41 located downstream of the first roller 40 and supporting the split reinforcing fiber bundle 50 from above, and a third roller 42 located vertically opposite the second roller 41 and supporting the split reinforcing fiber bundle 50 from above.

[0031] The third roller 42 holds down the split reinforcing fiber bundle 50 from above. Therefore, the first roller 40 and the third roller 42 can sandwich the split reinforcing fiber bundle 50 from above and below. The third roller 42 corresponds to the "holding roller" described in the claims. The first roller 40 and the second roller 41 are provided on the same line along the conveying direction of the reinforcing fiber bundle 50. The opening device 2, the splitting device 3, and the feeding device 4 constitute the splitting system 1.

[0032] Next, the operation of the above-mentioned fiber splitting system 1 will be described with reference to Fig. 1 and 3 to 7. First, as shown in Fig. 1, the reinforcing fiber bundle 50 is transported from the transport device to the fiber splitting system 1. By this transport, the reinforcing fiber bundle 50 transported from the transport device is supported from below by the first roller 20 of the fiber splitting device 2, supported from above by the second roller 21, and sandwiched between the third roller 22 and the fourth roller 23.

[0033] The spreading device 2 can spread the reinforcing fiber bundle 50 conveyed from the conveying device. Spreading here means crushing the round-shaft shaped reinforcing fiber bundle 50 to make it flat. In addition, by this conveyance, the reinforcing fiber bundle 50 conveyed from the conveying device is sandwiched vertically by the first roller 40 and the third roller 42 of the feeding device 4, and is supported from below by the second roller 41. The feeding device 4 can send out the reinforcing fiber bundle 50 spread by the spreading device 2 and the reinforcing fiber bundle 50 separated by the separating device 3 described later to the outside.

[0034] Next, the fiber splitting device 3 is started. Then, the first slit roller 30 of the fiber splitting device 3 descends (see FIG. 3). At this time, the first slit roller 30 rotates in the conveying direction due to frictional force against the surface of the conveyed reinforcing fiber bundle 50. That is, while the first slit roller 30 rotates, the first slit roller 30 descends so as to press against the surface of the conveyed reinforcing fiber bundle 50.

[0035] Therefore, the tip of the disk portion 30a of the first slit roller 30 bites into the surface of the opened reinforcing fiber bundle 50. The first slit roller 30 is also rotated by motor drive. Therefore, the tip of the disk portion 30a of the first slit roller 30 can be reliably caused to bite into the surface of the separated reinforcing fiber bundle 50.

[0036] Next, the second slit roller 31 of the fiber splitting device 3 rises while the first slit roller 30 of the fiber splitting device 3 remains lowered (see FIG. 4). That is, both the first slit roller 30 and the second slit roller 31 advance. This description corresponds to the claim that "the advance timing of the plurality of slit rollers is alternated so that the advance timing overlaps." At this time, the second slit roller 31 rotates in the conveying direction due to frictional force against the surface (in this case, the back surface) of the conveyed reinforcing fiber bundle 50. That is, while rotating, the second slit roller 31 rises so as to press against the surface (in this case, the back surface) of the conveyed reinforcing fiber bundle 50.

[0037] Therefore, the tip of the disk portion 31a of the second slit roller 31 bites into the surface (in this case, the back surface) of the split reinforcing fiber bundle 50. The second slit roller 31 is also rotated by motor drive. Therefore, the tip of the disk portion 31a of the second slit roller 31 can be reliably caused to bite into the surface of the split reinforcing fiber bundle 50.

[0038] Next, while the second slit roller 31 of the raised fiber separating device 3 remains raised, the first slit roller 30 of the fiber separating device 3 rises (see Figure 5). Next, while the second slit roller 31 of the raised fiber separating device 3 remains raised, the first slit roller 30 of the fiber separating device 3 descends (see Figure 6). In other words, both the first slit roller 30 and the second slit roller 31 are in an advanced state. This description corresponds to the claim that "the time timing of the advancement of the multiple slit rollers is alternated so that the time timing of the advancement overlaps."

[0039] Next, while the first slit roller 30 of the lowered fiber splitting device 3 remains lowered, the second slit roller 31 of the fiber splitting device 3 also descends (see FIG. 7). After that, returning to FIG. 3, the first slit roller 30 and the second slit roller 31 are alternately raised and lowered. Therefore, by the repeated biting of the disk portions 30a, 31a of the first slit roller 30 and the second slit roller 31, the reinforcing fiber bundle can be finely separated without removing not only the sizing agent but also the material impregnated with the matrix resin, and without placing a burden on the reinforcing fiber bundle 50.

[0040] In addition, because each of the disk parts 30a, 31a is circular, when the disk parts 30a, 31a press the surface of the reinforced fiber bundle 50, the reinforced fiber bundle 50 can be prevented from becoming frayed. The finely split reinforced fiber bundle 50 becomes a split body that is impregnated with the resin of the base material that forms the resin product (not shown). The split body is manufactured in this manner.

[0041] The fiber splitting device 3 for the reinforced fiber bundle 50 according to the embodiment of the present invention is configured as described above. According to this configuration, the fiber splitting device 3 includes a first slit roller 30 located downstream of the fiber spreading device 2 and supporting the spread reinforced fiber bundle 50 from above, and a second slit roller 31 located downstream of the first slit roller 30 and supporting the spread reinforced fiber bundle 50 from below. The first slit roller 30 and the second slit roller 31 are capable of ascending and descending (advancing and retreating) relative to the conveyed reinforced fiber bundle 50. Therefore, the tips of the disk parts 30a and 31a of the first slit roller 30 and the second slit roller 31 can bite into the surface of the conveyed reinforced fiber bundle 50. Therefore, by repeating the biting of the disk parts 30a and 31a of the first slit roller 30 and the second slit roller 31, the reinforced fiber bundle 50 can be finely split without removing not only the sizing agent but also the matrix resin impregnated material, and without putting a burden on the reinforced fiber bundle 50.

[0042] Furthermore, according to this configuration, the fiber splitting device 3 is equipped with a total of two slit rollers, the first slit roller 30 and the second slit roller 31. The first slit roller 30 and the second slit roller 31 are alternately raised and lowered. Therefore, even when splitting a reinforcing fiber bundle 50 in which the converged reinforcing fibers are not aligned in one direction (a reinforcing fiber bundle 50 in which the reinforcing fibers partially cross), for example, cutting or damage to the reinforcing fibers during the fiber splitting can be prevented.

[0043] Furthermore, according to this configuration, the fourth roller 23, which is a pressure roller, is provided upstream of the first slit roller 30. Furthermore, the third roller 42, which is a pressure roller, is provided downstream of the second slit roller 31. Therefore, in the fiber separating device 3, it is possible to suppress the vertical flapping of the reinforcing fiber bundle 50.

[0044] In addition, according to this configuration, the first slit roller 30 and the second slit roller 31 are mechanically connected to a motor, which is a driving means. Therefore, the first slit roller 30 and the second slit roller 31 can rotate freely and can also rotate (spin) by the motor drive. Therefore, the tips of the disk portions 30a and 31a of the first slit roller 30 and the second slit roller 31 can be reliably inserted into the surface of the separated reinforcing fiber bundle 50.

[0045] Furthermore, according to this configuration, the fiber splitting device 3 is equipped with a sensor capable of detecting the load acting on the first slit roller 30 and the second slit roller 31 from the reinforcing fiber bundle 50. When the load detected by this sensor exceeds a predetermined threshold, the first slit roller 30 rises from the reinforcing fiber bundle 50. The second slit roller 31 descends from the reinforcing fiber bundle 50. This makes it possible to prevent breakage or tearing of the reinforcing fibers during fiber splitting.

[0046] The method for splitting the reinforcing fiber bundle 50 according to the embodiment of the present invention is performed by the above-mentioned method. According to this method, the first slit roller 30 is lowered so as to come into contact with the surface of the reinforcing fiber bundle 50 being conveyed while rotating the first slit roller 30. Also, the second slit roller 31 is raised so as to come into contact with the surface (in this case, the back surface) of the reinforcing fiber bundle 50 being conveyed while rotating the second slit roller 31. Therefore, the tips of the disk parts 30a, 31a of the first slit roller 30 and the second slit roller 31 can bite into the surface of the reinforcing fiber bundle 50 being conveyed. Therefore, by repeating the biting of the disk parts 30a, 31a of the first slit roller 30 and the second slit roller 31, the reinforcing fiber bundle can be finely split without removing not only the sizing agent but also the matrix resin impregnated material, and without putting a burden on the reinforcing fiber bundle.

[0047] In addition, the above-mentioned method for splitting the reinforcing fiber bundles 50 can be used to produce split bodies by splitting the reinforcing fiber bundles 50 and impregnating them with resin.

[0048] The present invention is not limited to the above-described embodiment, and may be modified as appropriate as follows. In the embodiment, the fiber splitting device 3 is described as having a total of two slit rollers, the first slit roller 30 and the second slit roller 31. However, the present invention is not limited to this, and the fiber splitting device 3 may have only one of the first slit roller 30 and the second slit roller 31. Of course, the fiber splitting device 3 may have three or four slit rollers.

[0049] In the embodiment, the lifting angle θ1 of the first slit roller 30 (lifting angle with respect to the transport direction) is, for example, 90°. Also, the lifting angle θ2 of the second slit roller 31 (lifting angle with respect to the transport direction) is, for example, 90°. However, this is not limited to this, and these angles θ1 and θ2 may be any angle within the range of 60° to 120°.

[0050] In the embodiment, the operation pattern has been described in which the first slit roller 30 and the second slit roller 31 are alternately raised and lowered. However, the present invention is not limited to this, and the operation pattern may be such that the first slit roller 30 and the second slit roller 31 are simultaneously raised and lowered (see FIG. 8).

[0051] In the embodiment, the driving means mechanically connected to the first slit roller 30 and the second slit roller 31 is a motor. However, this is not limited to this, and the driving means may be various types of driving sources.

[0052] In the embodiment, the second slit roller 31 is provided downstream of the first slit roller 30. However, this is not limited to the above, and the second slit roller 31 may be provided at a position that faces the first slit roller 30 vertically across the reinforcing fiber bundle 50. In other words, the first slit roller 30 and the second slit roller 31 may be provided at positions that sandwich the reinforcing fiber bundle 50 between them vertically.

[0053] In the embodiment, a configuration in which one pair of the first slit roller 30 and the second slit roller 31 is provided has been described. However, the present invention is not limited to this, and a configuration in which multiple pairs of the first slit roller 30 and the second slit roller 31 are provided may also be used. In this case, the lifting and lowering operations of each of the multiple pairs of the first slit roller 30 may be synchronous or asynchronous. Of course, the lifting and lowering operations of each of the multiple pairs of the second slit roller 31 may be synchronous or asynchronous. Also, the multiple pairs of the first slit roller 30 and the second slit roller 31 may be lifted and lowered only on one side, either the upper side or the lower side.

[0054] In the embodiment, the first slit roller 30 and the second slit roller 31 are mechanically connected to the motor, which is the driving means. However, this is not limited to this, and the first slit roller 30 and the second slit roller 31 may be not mechanically connected to the motor, which is the driving means. In this case, the first slit roller 30 and the second slit roller 31 can rotate by frictional force from the surface of the conveyed reinforced fiber bundle 50.

[0055] Furthermore, "holding" by a holding roller may mean "holding with a single roller," "holding by sandwiching between multiple rollers," "holding with a flat surface on one side and a roller on the other side," etc.

[0056] In addition, in the embodiment, the fiber splitting system 1 is provided with the opening device 2, but if the reinforcing fiber bundle 50 is relatively flat, it may be transported directly from the transport device to the fiber splitting device 3. The feeding device 4 may not be provided, and the reinforcing fiber bundle may be mixed directly into resin or taken up. In that case, the upstream and downstream sides of the fiber splitting device 3 may be provided with only holding rollers that hold down the reinforcing fiber bundle. [Explanation of symbols]

[0057] 3 Separating equipment (separating equipment) 30 First slit roller (slit roller) 31 Second slit roller (slit roller) 50 Reinforced fiber bundle

Claims

1. A fiber splitting device for splitting reinforcing fiber bundles, A slit roller is provided which can rotate in a conveying direction by frictional force against a surface of the conveyed reinforcing fiber bundle, The slit roller advances and retreats relative to the reinforcing fiber bundle so as to be able to bite into the surface of the reinforcing fiber bundle, The slit roller is provided above and below the reinforcing fiber bundle, The multiple slit rollers provided above and below are alternately advanced and retreated relative to the surface of the reinforcing fiber bundle, and the multiple slit rollers are alternately advanced so that the time timing of their advancement overlaps, thereby ensuring that at least one of the upper and lower slit rollers is always advanced onto the surface of the reinforcing fiber bundle.

2. The fiber splitting device for reinforcing fiber bundles according to claim 1, A reinforcing fiber bundle splitting device having holding rollers for holding the reinforcing fiber bundle on the upstream and downstream sides of the slit roller.

3. A fiber splitting device for a reinforcing fiber bundle according to any one of claims 1 to 2, The slit roller is a reinforcing fiber bundle separating device that can rotate by a driving means.

4. A fiber splitting device for a reinforcing fiber bundle according to any one of claims 1 to 3, A sensor capable of detecting a load acting on the slit roller from the reinforcing fiber bundle is provided, A reinforcing fiber bundle splitting device in which the slit roller retracts from the reinforcing fiber bundle when the load detected by the sensor exceeds a predetermined threshold.

5. A method for splitting a reinforcing fiber bundle, comprising: A method for separating reinforcing fiber bundles, in which upper and lower slit rollers arranged to be able to advance and retreat relative to the reinforcing fiber bundle so as to be able to bite into the surface of the reinforcing fiber bundle are rotated in a conveying direction, while the slit rollers arranged above and below are alternately advanced and retreated on the front and back surfaces of the conveyed reinforcing fiber bundle so that one of the upper and lower slit rollers always advances relative to the reinforcing fiber bundle and the timing of the advances overlaps, to separate the reinforcing fiber bundle.

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