Method and apparatus for manufacturing a reinforcement profile

Abstract

A method for producing a reinforcement profile from at least one layer (1, 2, 3) cut from a pre-impregnated fiber web, the layer being placed on a core (4) which determines the profile shape and held in a placement area (6) on the core (4), and the layer being progressively pressed onto the core (4) starting from the placement area (6) transversely to the profile longitudinal direction until the profile longitudinal edge is reached. In order to create advantageous production conditions, it is proposed here that the layer (1, 2, 3) be progressively shaped and pressed onto the core (4) along the longitudinal direction of the core (4) by means of a plurality of shaping punches (8) which can be applied to the shaping surface of the core (4) and which are arranged mutually offset both in the peripheral direction of the core (4) and in the longitudinal direction of the core (4).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a reinforced profile from at least one layer cut from a pre-impregnated fiber web, wherein the layer is placed on a core that defines the profile shape and held in a placement area on the core, and the layer is progressively pressed onto the core transversely to the longitudinal edge of the profile from the placement area until reaching the longitudinal edge of the profile, and the present invention also relates to an apparatus for carrying out the method.

[0002] In particular, the aircraft industry uses reinforcing profiles made of fiber composite materials that extend along curved surfaces. This means that the layers cut from pre-impregnated fiber webs to construct such reinforcing profiles must not only be shaped to correspond to the profile cross-section transverse to the profile's longitudinal direction, but also follow a spatial curve along the profile's longitudinal direction. For this purpose, a core with a pre-defined profile shape and following a predetermined spatial curve along the longitudinal direction is used, and the individual layers of the reinforcing profile to be manufactured are shaped and pressed onto the core. Wrinkles and voids that affect the mechanical properties of the reinforcing profile should be avoided, as these often lead to time-consuming manual application of the layers when they are shaped and pressed onto the core. Background Technology

[0003] To mechanically manufacture multi-layered reinforced profiles from fiber composites, it is proposed (WO 2010 / 100386A2) that fiber webs, which will form the subsequent layers, are continuously pressed onto a core that is continuously fed relative to the rollers using rollers. Each fiber web is initially held on the core in a placement area by rollers that are staggered relative to each other both along and transverse to the longitudinal direction of the core. From this placement area, the fiber webs are progressively pressed onto the core transversely to the longitudinal edge of the profile by rollers that are spaced at intervals along the feed direction of the core. The rollers correspond to the transitions between the forming surfaces. However, a disadvantage is that the fiber webs accumulate in a wavy pattern in front of the rollers rolling under extrusion pressure, which particularly causes wrinkling.

[0004] To avoid this drawback, it is known (US 2016 / 0354982 A1) that individual layers cut from a pre-impregnated fiber web are sequentially placed on a core or on the previous layer applied to the core, and held relative to the core by a clamping device. Then, starting from the held placement area, a forming device progressively presses the layers transversely and longitudinally onto the core until reaching the longitudinal edge of the profile. The forming device, where the profile shape is generally largely symmetrical with respect to both sides of the central placement area, has forming tools acting on each layer. When loaded, the forming tools first press the layer onto the core immediately following the placement area, and then slide transversely along the longitudinal axis of the core under appropriate pressure until reaching the longitudinal edge. The resulting transverse stretching (Ausstreifen) of the layers along the forming surface of the core ensures fold-free forming of each layer; however, this can only be achieved by applying additional negative pressure to the layers. Since each layer is pressed onto the core during operation along its entire length, the forming tool must extend along the entire length of the profile. It should be considered that, due to the core's extension along a spatial curve, the forming tool must follow the resulting extension direction of the forming surface. For forming tools with two elastically bifurcated strips that divide into forming fingers via edge gaps, with corresponding layers loaded on either side of the placement area, this compensation is ensured by the fingers, which can deform independently within defined areas. However, a drawback is that the predetermined compaction of the layers or reinforcing profile cannot be achieved through these fingers.

[0005] To at least partially cure a reinforced profile consisting of pre-impregnated fiber webs bonded to a core in multiple layers using ultrasonic waves, it is also known (EP 2 873 517 A1) to press a suspended ultrasonic vibration unit onto the profile surface in an overlapping circumferential distribution and to move the core and the bonded fiber webs relative to the ultrasonic vibration unit along the profile's longitudinal direction. The pressure applied by the ultrasonic vibration unit allows the overlapping fiber webs to be additionally and collectively compacted. If we disregard the assumption that the fiber webs are already bonded to the core without folds, the risk arising from the relative movement between the ultrasonic vibration unit and the fiber webs along the profile's longitudinal direction is that the fiber webs move relative to each other and, especially, accumulate in front of the ultrasonic vibration unit as the regulating pressure increases. For this reason, a buffer membrane guided between the ultrasonic vibration unit and the reinforced profile can only reduce this risk, but cannot eliminate it; the same applies to the sliding layer on the ultrasonic vibration unit. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to provide a method by means of which at least one fiber web of a layer of a reinforcing profile to be formed can be progressively pressed into a core along the longitudinal direction of the profile without folding and compacted under the application of a preset pressure.

[0007] The technical problem is solved according to the present invention by means of a method of the aforementioned type, wherein the layer is progressively and gradually pressed onto the core along the longitudinal direction of the core by means of a plurality of forming punches arranged staggered along both the circumferential and longitudinal directions of the core and capable of acting on the forming surface of the core.

[0008] Because the forming punches are lifted from the sections of the layers formed by the forming punches and resting against the core between forming strokes, and move relative to the layers placed on the core along the longitudinal direction of the core in a conveying step for a new deformation step, the layers are gradually pressed onto the core without causing relative movement between the core and the forming device that would result in folding. Thus, due to the staggered arrangement of the forming punches and the gradual conveying step along the longitudinal direction of the profile, the fiber layer is progressively formed and pressed onto the core transversely along the longitudinal direction of the profile from its fixed placement area until it reaches the longitudinal edge of the profile. Since relative movement between the forming punches and the core along the longitudinal direction of the profile should be prevented during deformation, the core can, for example, be stopped between conveying steps. However, it is also possible for the forming device to move synchronously with the core during the loading of the forming punches, which allows for continuous conveying of the core. For continuous core feeding, it is also sufficient to equip the forming punch with a bracket that bends elastically along the profile longitudinally. This bracket compensates for the relative movement between the layers moving with the core and the forming punch supported on the forming device, which is fixed in position, during the working stroke. The unavoidable shear load of the fiber web does not cause any unacceptable irregularities during layer operation, because any longitudinal warping of the fiber layer resulting therefrom is restored by the inherent elasticity of the fiber web constituting the layer due to the release of the layer between working strokes. Since the relative movement between the core and the forming punch along the profile longitudinally is eliminated during fiber web forming, the disadvantages caused by such relative movement are avoided. This allows the fiber web layer to be formed progressively along the core, without the risk of fiber web wrinkling or warping, even under high extrusion pressures.

[0009] To manufacture multi-layered reinforced profiles, in addition to the first layer which is directly formed and pressed onto the core, each subsequent layer, cut from a pre-impregnated fiber web, is similarly placed on the previously formed layer and held in the placement area. It is then progressively formed and pressed onto the previously formed layer from the placement area to the longitudinal edge of the profile by means of a plurality of forming punches arranged staggered both circumferentially and longitudinally along the core. Each layer can be compacted during its deformation process. Uniform compaction along the length of the layer is contingent upon the length of the conveying step matching the length of the forming punches, which thus deform the area connected to the previously deformed longitudinal segment of the layer after each conveying step, or the deformed areas overlap.

[0010] To manufacture a reinforced profile from multiple layers cut from a pre-impregnated fiber web, this can be achieved using equipment having a core that defines the profile shape, a clamping device that holds the layers in a placement area of ​​the core, and a forming device for shaping the layers onto a forming surface of the core. The forming device is capable of acting towards the forming surface of the core, and has forming punches arranged staggered from each other both along the longitudinal and axial directions of the core. This creates the design prerequisite for progressively and continuously pressing each fiber web layer onto the core or the previous fiber web layer applied to the core, provided that the forming device and the core can be gradually displaced relative to each other along the longitudinal direction of the core.

[0011] The step length of the relative displacement between the forming device and the core is equal to or less than the longitudinal length of the forming punch measured along the core. This allows each forming punch to be used sequentially without gaps, or in the longitudinal sections of the overlapping fiber web layers. After multiple feed steps corresponding to the length of the forming device, the fiber web is locally deformed into the profile shape determined by the core. Further feed steps press the fiber web layer completely onto the core or the previously applied fiber web layer, thereby extending the longitudinal section of the deformation.

[0012] To allow for easy modification of the forming apparatus for different profile shapes, the replaceable forming punches, which can be used as needed, are each pivotally supported on a slide that is longitudinally movable transverse to the core, about an axis extending longitudinally along the core. This allows the forming punches to be adapted in terms of distance and orientation to the corresponding profile shape of the reinforced profile to be manufactured. Relatedly, the forming punches and servo cylinders form a structural unit pivotally supported on the slides, resulting in particularly simple design conditions.

[0013] The forming apparatus is advantageously equipped with the clamping device, however, this is not necessary. Attached Figure Description

[0014] The method according to the invention is described in detail with reference to the accompanying drawings. In the drawings:

[0015] Figure 1 A cross-section obtained by transversely slicing the core shows an apparatus according to the invention having a molding device for manufacturing reinforced profiles.

[0016] Figure 2 The device is shown in a side view taken in the direction of arrow II, and

[0017] Figure 3 A top view of the core is shown within the scope of the forming apparatus; however, only the loadable forming punches of the forming apparatus are shown in the distribution of the forming punches. Detailed Implementation

[0018] The apparatus shown for manufacturing a reinforced profile, typically consisting of multiple layers 1, 2, 3 (i.e., the load-bearing layer 2 in the embodiment) and two covering layers 1 and 3, has a core 4 that defines the profile shape, such as a cap-shaped profile, and the longitudinal orientation of the profile. Layers 1, 2, 3, cut from a pre-impregnated fiber web, are sequentially pressed onto the forming surface of the core using a forming device 5. The forming device 5 includes, on one hand, a clamping device 7 for holding layers 1, 2, 3 on a placement area 6 of the core 4, and on the other hand, a forming punch 8 oriented towards the forming surface of the core 4 and loaded by a servo drive 9. The forming punches 8 are staggered from each other both along the longitudinal and circumferential directions of the core 4, so that layers 1, 2, 3 can be sequentially and progressively pressed onto the core 4 or onto the previously applied layers 1, 2. The forming punches 8 are arranged in pairs on either side of the placement area 6 due to the high degree of profile symmetry. In order for the forming punch 8 to automatically orient itself toward the forming surface of the core 4, the forming punch 8 can be supported by a limited, freely pivoting bracket or has an elastically bending bracket.

[0019] The servo drive 9 is preferably designed as a servo cylinder forming a structural unit with the forming punch 8. This servo cylinder is pivotally supported in a slide 11 about an axis 10 formed along the longitudinal direction of the core 4 and can be pivotally adjusted by means of a pivot drive 12. The slide 11 itself is movably guided on a guide 13 extending transversely to the longitudinal direction of the core 4 within a support 14 and can be adjusted along the guide 13 by a drive 15. The forming device 5 can be oriented relative to the longitudinal direction of the core 4 via, for example, a universal joint 16 for operating the machinery, so as to move along the stationary core 4 or be statically held relative to the longitudinally movable core 4.

[0020] To manufacture a reinforced profile, after the forming device 5 is oriented toward the core 4 and the forming punch 8 is oriented toward the forming surface of the core 4, the first layer 1 is placed in the placement area 6 of the core 4 and held toward the core 4 by means of the clamping device 7 by controlling the servo drive 17 correspondingly to the clamping device 7. If the paired forming punches 8, which are connected to the placement area 6 along the circumference of the core 4, are controlled in this initial position, the forming punches 8, loaded by the servo drive 9, press the layer 1 onto the core 4 in the transition area from the bottom of the cap-shaped profile to the sidewall, wherein the layer 1 is formed from the core 4 in the first deformation step. Figure 1 The initial position, indicated by the dotted line, curves to the middle position, indicated by the dashed line, around the longitudinal edge of the core 4, which defines the transition region.

[0021] exist Figure 3 In the diagram, the undeformed starting portion 18 of the first layer 1, located in the region of the first pair of forming punches 8 within the introduction forming device 5, is represented by a solid line. The deformation of the starting portion 18, held in the placement area 6 by means of the clamping device 7, by the first pair of forming punches 8 is represented by a dashed line. With each conveying step, the core 4, together with the first layer 1, moves a distance as the clamping device 7 and the forming punches 8 are lifted. This distance is chosen to be less than the length of the forming punches 8 measured along the longitudinal direction of the profile, so that after each conveying step, the first pair of forming punches deforms the layer 1, thereby causing the layer 1 to be continuously deformed along its length in the region of the circumferential segment defined by the first pair of forming punches under appropriate pressure in successive deformation steps.

[0022] According to the embodiment shown, the starting portion 18, which is bent between the bottom and sidewalls of the cap-shaped profile by the first pair of forming punches around the longitudinal edge of the core 4, reaches the area of ​​the second pair of forming punches 8, as shown by the thin dashed line, after three transport steps corresponding to arrow 19. In this starting position, the starting portion 18 can be pressed against the sidewalls of the cap-shaped profile defined by the core 4 by means of the second pair of forming punches in the second deformation step, which is indicated by the thicker dotted outline shape of the starting portion 18.

[0023] Due to the uniform spacing between the forming punches along the longitudinal direction of the profile, another pair of forming punches 8, which are staggered in the circumferential direction of the core 4, are used after three additional conveying steps until the first layer 1 has the profile shape preset by the core 4 at the exit of the forming device 5 by the last pair of forming punches that terminates the deformation process.

[0024] With each additional conveying step, the fully formed longitudinal section of the first layer 1 extends until, after complete completion, the second layer 2 can be applied in a similar manner to the first layer 1, which is molded and abuts the core 4. Layers are applied repeatedly until the final layer 3, before the molded reinforcing profile is removed from the core 4 after at least partial curing of the pre-impregnated fiber web, if necessary.

[0025] Because the individual layers 1, 2, and 3 are pressurized onto the core 4 or the previously applied layers 1 and 2 by the clamping device 7 and the forming punch 8, the individual layers 1, 2, and 3 can be compacted to meet the corresponding requirements, wherein the thickness of the corresponding layer can be detected by using the servo drive 9 or 17. To improve the compaction effect, the clamping device 7 and the forming punch 8 can be loaded by a vibration drive.

Claims

1. A method for manufacturing a reinforced profile from at least one layer (1) cut from a pre-impregnated fiber web, wherein the layer is placed on a core (4) defining the profile shape and held in a placement area (6) on the core (4), and the layer is progressively pressed onto the core (4) transversely to the longitudinal direction of the profile, starting from the placement area (6) until reaching the longitudinal edge of the profile, characterized in that, The layer (1) is pressed onto the core (4) gradually and progressively along the longitudinal direction of the core (4) by means of a plurality of forming punches (8) that are staggered along both the circumference and the longitudinal direction of the core (4) and can apply force to the forming surface of the core (4).

2. The method according to claim 1, characterized in that, In order to manufacture multi-layered reinforced profiles, in addition to the first layer which is directly formed and pressed onto the core (4), each additional layer (2, 3) cut from the pre-impregnated fiber web is placed on the previously formed layers (1, 2) in a similar manner and held in the placement area (6) and then progressively pressed onto the previously formed layers (1, 2) from the placement area (6) to the longitudinal edge of the profile by means of a plurality of forming punches (8) arranged both circumferentially and longitudinally of the core (4).

3. An apparatus for manufacturing a reinforced profile from a plurality of layers (1, 2, 3) cut from a pre-impregnated fiber web, the apparatus comprising a core (4) defining the shape of the profile, a clamping device (7) for holding the layers (1, 2, 3) in a placement area (6) of the core (4), and a forming device (5) for shaping the layers (1, 2, 3) onto a forming surface of the core (4), characterized in that, The forming device (5) can apply action toward the forming surface of the core (4), and the forming device has forming punches (8) that are staggered from each other both along the longitudinal direction and the axial direction of the core (4), and the forming device (5) and the core (4) can gradually move relative to each other along the longitudinal direction of the core (4).

4. The apparatus according to claim 3, characterized in that, The step length of the relative displacement between the forming device (5) and the core (4) is at most equal to the length of the forming punch (8) measured along the longitudinal direction of the core (4).

5. The apparatus according to claim 3 or 4, characterized in that, The replaceable forming punch (8) itself is pivotally supported on a longitudinally movable slide (11) that is transverse to the core (4) about an axis (10) extending longitudinally along the core (4).

6. The apparatus according to claim 5, characterized in that, The forming punch (8) and the servo cylinder form a structural unit that is pivotally supported on the slide (11).

7. The apparatus according to claim 3 or 4, characterized in that, The forming device (5) has the pressing device (7).

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