EP1153180A1

EP1153180A1 - Device for splitting the ends of a fibre strand consisting of a bonded fibre material

Info

Publication number: EP1153180A1
Application number: EP00903477A
Authority: EP
Inventors: Gregor Schwegler
Original assignee: Stress Head AG
Current assignee: Sika Schweiz AG
Priority date: 1999-02-23
Filing date: 2000-02-18
Publication date: 2001-11-14
Anticipated expiration: 2020-02-18
Also published as: ATE265591T1; WO2000050706A1; AU762553B2; AU2530900A; CA2362155A1; DE50006243D1; US20020000300A1; EP1153180B1

Abstract

A device for splitting the ends of strands of laminar bonded fiber material, preferably carbon fiber-reinforced lamellae, into two or more end piles with a cutter, accurately to the measurements. The device includes a positioning device which enables the cutter to be aligned exactly in relation to the end of the fiber strand. In one embodiment, the carbon fiber lamella is fixed on a bearing table in a cutting position and a cutter that is pivotally mounted on the table is manually pivoted through the lamella end. In another embodiment, the cutter is held in a cutter slide and can be linearly displaced together with the same along a slide guide. Yet another embodiment includes a planing device in which the cutter is fixed and placed on the lamella end, the lamella end being guided through a linear guide and onto the cutter directly at the front in a manner which is accurate to the measurements and split into the desired number of end piles.

Description

Device for splitting the ends of a fiber strand made of fiber composite material

The invention relates to a device for splitting the ends of fiber strands made of a composite material, in particular a CFRP lamella for reinforcing structures, with a cutting edge.

To increase the load-bearing capacity of support structures on existing buildings, fiber composite materials have proven themselves, which are glued flat, for example in the form of lamellae made of carbon fiber reinforced plastic, so-called CFRP lamellae, under tension on the tension side of the support structure. Of particular importance is the introduction of the preload force on the CFRP lamella via end elements. The ends of the CFRP lamella are split along the grain in at least two end tabs and non-positively connected, preferably glued, to the end element, as is shown in the unpublished Swiss patent application No. 1997 1987/97. By splitting, an advantageous enlargement of the adhesive surface is achieved without the strength properties of the CFRP lamella being impaired in the direction of pull.

Due to the small cross-sectional thickness of the lamella, it is important to obtain the desired end tab thickness and to avoid cutting the lamella. If an end flag is too thin, there is a great risk that the brittle fibers will be kinked due to the spreading of the end flags during assembly or fixing in the connecting element on the building and will no longer be available for introducing the pretensioning force via the connecting element into the lamella stand. The invention is therefore based on the problem of creating a device which enables the lamella ends to be separated in a simple manner.

A positioning device for the fiber strand, on which the cutting edge is fixed, is used for this purpose. The cutting edge and the positioning device are fixed in their position relative to one another, so that the fiber strand is aligned or positioned in the desired manner in its position relative to the cutting edge. The cutting edge can be attached precisely to the end of the fiber strand and thus split off end tabs with the desired layer thickness in a targeted and repeatable manner. Due to the laminar structure, the cutting edge penetrates across the cross-sectional width in the longitudinal direction of the fiber into the fiber composite material and splits a layer of the brittle that is fixed in the matrix but is brittle in the direction of the fiber

Fibers. The sharpness of the cutting edge is therefore chosen so that it only penetrates the matrix of the lamella and does not cut through the individual fibers. A cutting knife with a thin back of a few millimeters is best used to avoid breaking off possibly thin end flags during the cutting process.

According to a preferred embodiment of the invention, the positioning device is designed as a support table with a flat support surface. In the area of the contact surface, a two-dimensional guide ensures that the slat end to be split is aligned with the cutting edge in the desired cutting position. The slat brought into the cutting position is fixed in position on the support table by means of a hold-down device. The cutting edge, together with a peeling knife carrying it, is pivotably articulated on the support table about a pivot axis provided perpendicular to the support surface. The peeling knife lies with its flat underside on the support surface, which means that the cutting edge when the Exact guidance in the direction of the peeling knife in the direction of the lamella.

The guide ensures that on the one hand the lamella is supported in the cutting / swiveling direction of the peeling knife and on the other hand end tabs with the desired thickness are split off or peeled off. The latter is preferably adjustable via the support position of the lamella on the support surface. In one version, gauges are used that specify the contact level of the lamella on the contact surface for setting the end lug thickness and through which the cutting edge attaches to the desired position on the lamella cross-section.

According to another exemplary embodiment, it is advantageous with regard to an exact cut if the cutting edge does not at the same time lie against the end face of the lamella over the entire width, but rather the position of the pivot axis in relation to the cutting edge attachment is selected such that the cutting edge attaches to an edge . The cutting edge penetrates effortlessly at the desired level and experiences at the next level

Cutting movement due to the laminar structure of the lamella.

According to another preferred exemplary embodiment of the invention, the positioning device is again as

Support table designed for the slat end to be split. As in the exemplary embodiment described above, a lateral guide and gauge plates for embedding the lamella serve to bring the lamella into the desired cutting position, in which it is finally fixed by means of hold-down devices.

However, the cutting edge is moved translationally towards the positioned slat end. Here, too, the cutting edge lies on the contact surface, but is held in a knife carriage and along it along one Slide guide can be moved relative to the support table. The slide guide comprises two guide rods, which are preferably arranged laterally on the support table and parallel to the translation movement and on which the knife slide is fixed so as to be axially displaceable. This parallel guidance gives the cutting edge a particularly precise guidance, which is why this design is highly suitable for peeling or splitting off several and thinner end tabs.

Knife slide and slide guide are robust and stable. Furthermore, the cutting edge is arranged closely on the support table and does not protrude laterally, so that the risk of injury to the operator and the risk of damage to the cutting edge are low. For the reasons mentioned, this embodiment offers advantages when installing the lamella on the construction site.

In a further particularly preferred embodiment of the invention, the positioning device and the cutting edge are firmly connected to one another in a planer. The positioning device forms a guide for the lamella, on the basis of which the lamella can only be pushed and moved in the longitudinal direction on the free end of the lamella. The guide is oriented in such a way that the end of the slat ends directly on the cutting edge and is split into end tabs. This version is particularly simple and robust; it enables the slat end to be split without first clamping or fixing the slat to the positioning device, and is therefore particularly easy to use. In addition, the cutting edge is in the

Positioning device embedded and therefore protected against damage and does not pose any risk of injury to the user. Due to its compact design, the planer version is particularly well suited for use on the construction site, where every reinforcement slat is attached to the respective one required dimensions can be adjusted and the connection elements can be installed.

Three exemplary embodiments of the invention are described in detail below with reference to the drawing. It shows:

Figure 1, a peeling knife as the first embodiment of the invention in plan view;

Figure 2 is a schematic cross-sectional view of the peeling knife along the section II-II in Figure 1;

Figure 3 is a schematic detailed view III of Figure 2;

Figure 4, schematically a second embodiment of the

Invention with translationally movable cutting edge;

Figure 5 shows schematically a third embodiment of the invention;

Figure 6 is a half sectional view of that shown in Figure 5

Embodiment along the section VI-VI;

Figure 7 shows a cross section through a reinforced concrete beam with CFRP lamella attached to the underside with a schematic cross section through an end element of a CFRP lamella.

FIG. 1 shows a first embodiment of the device 1 according to the invention. The device 1 essentially comprises

Assemblies a support table 2, a hold-down device 3 and a peeling knife 4 pivotably articulated on the support table 2.

The support table 2 has a rectangular base area and a flat support surface 5. Over the entire length of the

The support table 2 is on one half of the support surface 5 Positioning groove 6 is incorporated, the U-shaped cross section of which, as shown in FIG. 2, is delimited by a flat groove base 7, a first flank 8 and a second flank 9 of a stop bar 10 running parallel to it.

The groove depth 11 depends on the thickness of the lamella 12 to be split and the desired thickness 13 of the end lug to be split / peeled off. In general, the groove depth 11 is selected such that the CFRP lamella 12 inserted into the positioning groove 6 projects beyond the positioning groove 6 by the desired amount of the end lug thickness 13. In order to be able to set the thickness 13 of the end lugs to be split off independently of the lamella thickness, in the exemplary embodiment shown in FIGS. 1 to 3, a gauge plate 14 is additionally inserted into the positioning groove 6. The CFRP lamella 12 resting thereon can be underbedded over the thickness 15 of this gage sheet 14 until the desired layer or end lug thickness 13 projects beyond the positioning groove 6, which can be clearly seen in FIG. 3.

The width 16 of the positioning groove 6 is chosen to be slightly larger than the width of about 80 mm of a CFRP lamella 12, the end 17 of which is to be split into end tabs. Basically, the positioning groove β is to be provided with the same width or width than the CFRP lamella 12, so that it is ensured in any case that the CFRP lamella 12 finds sufficient space in the positioning groove 6 and lies flat on the groove base 7 or the gauge plate 14. Regardless of the actual slat width, the slat 12 lies laterally against the stop bar and is clamped down by means of a hold-down device 3 described below and fixed in its position. A scale 19 is formed along the stop edge 18 of the stop bar 10, starting from the hold-down device 3. It serves to align the free end 17 of the CFRP lamella in the positioning groove 6 to the desired length of the end tabs.

The hold-down 3 lies with a flat contact surface 20 facing the support surface 5 on the CFRP lamella 12 and is screwed against the support surface 5 with four lag screws 21. The bolts 22 are anchored in the support table 2 and protrude through the hold-down device 3 through four correspondingly arranged bores 23. A wing nut 24 is screwed onto the free ends of the screw bolts 22 projecting above the hold-down device 3 and is supported on the hold-down device 3 and presses it down. Instead of the tension screws 21 with wing nuts 24, other quick fastening means or devices are also possible.

For example, the hold-down device 3 can be connected to the support table 2 on one side via a hinge or the like, and the opposite side can be pressed down onto the CFRP lamella 12 using a quick-release fastener or a quick-release screw. A hold-down device that can be folded in this way is particularly easy to use.

On the support table 2, on the side opposite the stop bar 10, one end of a peeling knife 4 is pivotably articulated about a pivot axis 25 provided perpendicular to the support surface 5. The length of the peeling knife 4 is dimensioned such that it projects beyond the support table 2 with its other end, which is designed as a handle 26. With the exception of the handle 26, the one facing the positioning groove 6 Side of the paring knife 4 is ground obliquely and forms the cutting edge 28 with the underside 27 along the common edge. The underside 27 of the peeling knife 4 is shown flat and lies on the support surface 5, as a result of which the cutting edge 28 is then guided precisely when the peeling knife 4 is pivoted about the pivot axis 25. The position of the pivot axis 25 and also the position of the cutting edge 28 relative to the fixed CFRP lamella 12 is selected such that the cutting edge 28 pivoted by hand into the position shown in broken lines in FIG. 1 meets the CFRP lamella 12 at the corner edge 29 and there the cut can be made precisely at the level of the contact surface 5. As soon as the cutting edge 28 has penetrated the fiber strand laminate of the CFRP lamella 12 and the cut has been made, the peeling knife 4 can be pivoted by hand into its end position parallel to the hold-down device 3. In Figure 4, a second embodiment of the invention is shown, in which a support table 30 is provided, in which a lateral guide 31 and gauges 32 serve to support the CFRP lamella 33 to bring the lamella 33 into the desired cutting position in which it is finally fixed by means of hold-down 34. In contrast to the previous example, the cutting edge 35 is now moved translationally towards the positioned slat end 36.

The cutting edge 35 is held in a knife carriage 37 and, together with the latter, can be displaced along the carriage guide 38 relative to the support table 30 on the support surface 39. The slide guide 38 comprises two guide rods 41 arranged laterally on the support table 30 parallel to the translation direction 40 and which are screwed to a beam connection 42 with two supports 43, 44 at both ends. A carrier 43 is fastened to the front 45 and the carrier 44 to the rear 46 of the support table 30 by means of screw connections 47. At this firmly connected to the support table 30 Carriage guide 38, the knife carriage 37 is fixed axially displaceably.

The knife carriage 37 comprises two sliding sleeves 48 which are attached to the guide rods 41 and enclose them. The sliding sleeves 48 are firmly connected to one another via a cutter holder 49. In imaginary extension of the tailor's carrier

49 are freely projecting rod-shaped handles on both sides

50 arranged with which the stiff knife carriage can be moved by hand.

Instead of the handles 50, it is also possible to move the knife carriage 37 by means of a lever or screw mechanism, not shown here. A lever mechanism can be articulated on the sliding sleeves 48, the tensile force of which is introduced into the support table 30 via a suitable kinematics.

A blade 51 with a straight or, as shown here, inclined cutting edge 35 is fixedly connected to the cutter carrier 49. Due to the inclined cutting edge, the cutting edge 35 first meets a corner edge 52 of the end-side lamella end 36. There the cutting edge 35 penetrates the fiber laminate at certain points and thus starts the cut. When the knife carriage 37 is moved further, the cutting edge 35 then splits or peels off the desired laminate layer.

The knife carriage 37 and the blade 51 attached to it have a cross-sectional profile which is wedge-shaped in the cutting direction and which serves as a guide for the split-off laminate layer when the cutting edge 35 penetrates and the splitting end progressively splits. FIGS. 5 and 6 show an embodiment of the device according to the invention in the form of a plane 52. The planer 52 differs from the previously described embodiments of the invention by fixed in

a positioning device 53 anchored cutting edges 54. With regard to the mode of operation in this embodiment as a planer 52, the CFRP lamella 55 is not fixed in the cutting position on the positioning device 53, but the cutting edge 54 and guide of the CFRP lamella 55 are structurally clear in their position relative to one another fixed and are moved as a one-piece device overall relative to the CFRP lamella 55. When moving, the free slat end 56 is split into the desired number of end tabs in one operation.

The planer 52 form a first side part 57, a second side part 58 between which a first guide block 59 and a second guide block 60 are firmly clamped by means of four clamping screws 61. Side parts 57, 58 and guide blocks 59, 60 are preferably made of a metal material such as aluminum; however, they can also be made of plastic or wood.

The first guide block 59 and the second guide block 60 delimit a guide slot 62 between them in the longitudinal direction of the plane, which diverges in a wedge shape toward the rear 63. The guide slot 62 has a rectangular cross section over a length 64 from the front side 65 to the transition 66 into the wedge-shaped funnel 67, the clear distance 68 between the first guide block 59 and the second guide block 60 with the aid of in the two guide blocks 59, 60 formed elongated holes 69 can each be adapted to the thickness of the slat end 56 to be split. The width of the guide slot 62 is structurally fixed to one dimension; In any case, it is expediently chosen to be larger than the slat width. Axially aligned with the guide slot 62, two knife blades 70 protrude from the rear 63 so far into the wedge-shaped funnel 67 that their cutting edges 54 extend up to the rectangular guide slot 62. The knife blades 70 extend over the entire width of the plane 52 and are combined in a knife insert 71 to form an assembly which is fixedly mounted in the complementary recesses 73, 74 in the side parts 57, 58 by means of plug pins 72. In addition to the two knife blades 70, the knife insert 71 comprises three spacers 75 on each side, by means of which the mutual distance 76 of the knife blades 70 and thus the layer thickness of the end tabs can be determined. At the same time, the position of each individual knife blade 70 and / or the knife insert 71 with respect to the guide slot 62 can be aligned and adjusted by suitable thickness adjustment.

For anchoring the knife insert 71, two bores are provided one behind the other in the spacers 75 and knife blades 70 perpendicular to the blade plane. The position of the bores corresponds to bores 77 in the side parts 57, 58, through which the plug-in bolt 72, which fixes the knife insert 71, is inserted in the assembled state.

FIG. 7 shows a cross section through a reinforced concrete beam 78 with CFRP lamella 79 glued to the underside (tension side), at the ends of which end elements 80 and 81 are attached. In the end elements 80 and 81, three holding slots 82, 83, 84 are formed one above the other and spread out in a wedge shape, into each of which one of three end tabs 85 is glued, into which the end of the CFRP lamella 79 is split is. This improves the introduction of tensile forces into the CFRP lamella 79 via the end elements 80, 81.

Claims

Claims:

1. Device for splitting the ends of a fiber strand made of fiber composite material, such as CFRP lamellae, in particular for use as a reinforcing element for buildings, with a

Cutting edge (28), (35), (54), the cutting edge (28), (35), (54) cooperating with a positioning device (2), (30), (53) on which the fiber strand (12) , (33), (55) is fixed in its position to the cutting edge (28), (35), (54).

2. Device according to claim 1, characterized in that the fiber strand (12), (33), (55) can be positioned relative to the cutting edge (28), (35), (54) in such a way that end tabs (85) of approximately the same thickness arise.

3. Device according to claim 1 or 2, characterized in that the fiber strand (12), (33), (55) relative to the cutting edge (28), (35), (54) can be positioned in two or more positions to produce at least three or more end tabs (85) of the same thickness.

4. The device according to claim 1, characterized in that the cutting edge (28) is pivotally articulated on the positioning device (2).

5. The device according to claim 1, characterized in that the cutting edge (35) is translationally connected to the positioning device (30).

6. The device according to claim 1, characterized in that the cutting edge (54) is fixedly connected to the positioning device (53).

7. The device according to claim 1, characterized in that a support table (10), (30) with at least one two-dimensional guide (7, 9), (31), (62) for the fiber strand (12), (33), ( 55) is provided, by means of which the fiber strand (12), (33), (55) is held in the desired cutting position in its position relative to the cutting edge (28), (35), (54).

8. Device according to one of claims 1 to 8, characterized in that the fiber strand (12), (33), (55) in its position to the cutting edge (28), (35), (54) by means of a tensioning device (3) , (34) on the positioning device (2), (30) can be fixed.