Application head comprising a cutting system with integrated control in translation and in rotation

Abstract

An application head specially designed for producing parts made of composite materials, comprising an application roller, guiding means defining a guiding plane and a cutting system for cutting a fiber comprising a first tool movable in translation along a cutting direction and a second tool. The cutting system comprises an integrated control means able to displace the first tool in translation along the cutting direction and to displace the first and second tool together, in rotation around a direction parallel to the application roller.

Claims

1. Application head specially designed for producing composite material parts, comprising an application roller presenting a rotation axis, guiding means defining a guiding plane and a cutting system for cutting a fiber guided by the guiding means and applied by the application roller, the cutting system comprising a first tool movable in translation along a cutting direction and a second tool, wherein the cutting system comprises an integrated control means able to displace at least the first tool in translation along the cutting direction and to displace the first and second tool together, in rotation around a direction parallel to the rotation axis of the application roller.

2. Application head according to claim 1, wherein the integrated control means is able to displace the first tool and the second tool in translation along the cutting direction.

3. Application head according to claim 2, wherein the integrated control means comprises a control lever movable around a first rotation axis and provided with a first lever arm articulated to a first tool holder carrying the first tool and a second lever arm articulated, by means of a link , to a second tool holder carrying the second tool, said second lever arm being controlled in displacement by a cylinder rod, said first blade holder being articulated to a second rotation axis by means of a link and said first and second tool holders being connected together by a sliding connecting means for sliding along the cutting direction.

4. Application head according to claim 1, wherein the first tool comprises a first blade provided with a bevel defining a first cutting edge, the second tool comprises a second blade provided with a bevel defining a second cutting edge, said bevels being opposed to allow an overlapping of said cutting edges.

5. Application head according to claim 4, wherein the first and second cutting edges are rectilinear, and at least one of the two cutting edges is inclined relative to the guiding plane, so that the two cutting edges form a cutting angle between them.

6. Application head according to claim 5, wherein the first cutting edge and the second cutting edge are inclined so that the bisector of the cutting angle between the first cutting edge and the second cutting edge is perpendicular to the cutting direction.

7. Method for manufacturing a composite material part comprising the application of continuous fibers onto an application surface, wherein the application of fibers is carried out by means of a fiber application head according to claim 1, by relative displacement of the application head with respect to the layup surface along layup trajectories.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of the cutting system according to a first embodiment of the invention, showing the blades in an initial position along the guiding plane and in two inactive positions along the cutting direction.

(2) FIG. 2 is a schematic view of the cutting system, showing the blades in an end position along the guiding plane and in two active positions along the cutting direction.

(3) FIG. 3 is an enlarged partial view of the cutting system in FIG. 1.

(4) FIG. 4 is an enlarged partial view of the cutting system in FIG. 2.

(5) FIG. 5 is an enlarged view of the blades shown in FIG. 1, in top view.

(6) FIG. 6 is an enlargement of the blades shown in FIG. 2, in top view.

(7) FIG. 7 is a schematic view of an application head, showing the cutting system and a clamping system in initial positions along the guiding plane.

(8) FIG. 8 is a schematic view of the application head in which the blades of the cutting system have displaced to an end position in the guiding plane.

(9) FIG. 9 is a schematic view of the application head, in which the clamping tools of the clamping system have displaced into an end position in the guiding plane.

(10) FIG. 10 is a schematic view of the application head, in which the blades of the cutting system are again in the initial position in the guiding plane.

DETAILED DESCRIPTION

(11) According to a first embodiment of the invention, illustrated by FIGS. 1 to 6, an application head comprises an application roller 1, and for each fiber, guiding means 3 defining a guiding plane P for guiding the fiber entering into the head along a guiding plane towards the roller, and a cutting system 5. The guiding means of a fiber are for example formed by a guiding channel formed at the assembly interface of two plates, the guiding plane corresponding to a median longitudinal plane of the channel. When the head is intended for the application of a strip of several fibers, the head comprises a guiding channel for each fiber and a cutting system for each fiber, and may comprise a single roller for applying all the fibers, or several rollers, for example one roller for each fiber. Other guiding means may include tube sections or one or more pulleys.

(12) The cutting system 5 comprises first and second blades 51, 53 movable in translation along a cutting direction T.sub.c between two inactive positions κ.sub.1, κ.sub.3 and two active positions κ.sub.2, κ.sub.4. Said blades 51, 53 are movable together between an initial cutting position ψ.sub.1 and a final cutting position «.sub.2 representing a variation in distance along the guiding plane P.

(13) An integrated control means 6 is adapted to displace the first and second blades 51, 53 in translation along the cutting direction T.sub.c and to displace them together between the initial cutting position ψ.sub.1 and final cutting position ψ.sub.2, in rotation around a direction parallel to the axis 11 of the application roller 1, the integrated control means being adapted to displace the blades between their inactive and initial positions and their active and final positions.

(14) The integrated control means comprise a control lever 61 movable around a first rotation axis A.sub.1 and provided with a first lever arm 63 and a second lever arm 65, 66. A first blade holder 57 carrying the first blade 51 is articulated to the first lever arm 63. A second blade holder 59 carrying the second blade 53 is articulated to the second lever arm 65, 66 by means of a link 69. The lever 61 is controlled in displacement by the rod 67 of a cylinder, articulated to the second lever arm 65, 66. The first blade holder 57 is articulated to a second rotation axis A.sub.2 by means of a link 60 and said first and second blade holders 57, 59 being connected to each other by a sliding connecting means 68 for sliding along the cutting direction.

(15) The rotation axes A.sub.1 and A.sub.2 are fixed with respect to a support structure of the application head, the cylinder being fixedly mounted by its cylinder body to said support structure. It should be noted that the connection between the cylinder rod 67 and the intermediate link 66 has a clearance, for example in the form of an oblong slot. Alternatively, the cylinder is mounted with a clearance with respect to the mounting support structure.

(16) The rotation axes A.sub.1 and A.sub.2 are parallel to the guiding plane P and the rotation axis 11 of the compaction roller. The first lever arm 63 is articulated by its end to the first blade holder 57 around a pivot axis A.sub.3, and the second lever arm is articulated by its end to the cylinder rod around a pivot axis A.sub.4, the two lever arms forming an angle between them, the axes A.sub.1, A.sub.3 and A.sub.4 being not contained in a same plane. The link 69 is articulated by a first end to the second blade holder 59 around a pivot axis A.sub.5 and by its second end to the second lever arm around a pivoting axis A.sub.6, this pivot axis A.sub.6 being arranged between axis A.sub.1 and axis A.sub.4, on the side of the plane passing through axis A.sub.1 and axis A.sub.4 which is opposite to axis A.sub.5. In the present embodiment shown in the figures, the axes A.sub.1, A.sub.3 and A.sub.6 are aligned, contained in the same plane, and the distance between the axes A.sub.1 and A.sub.3 is equal to the distance between the axes A.sub.1 and A.sub.6. The rotation axis A.sub.2 is arranged on the side of the plane passing through the axes A.sub.1 and A.sub.3 which is opposite to the blades and to the axis A.sub.5, the link 60 being articulated at one end around the fixed axis A.sub.2 and at the other end to the first blade holder around a pivot axis A.sub.7 which is arranged on the same side of the plane passing through the axes A.sub.1 and A.sub.3 as the axis A.sub.2. The pivot axes A.sub.3-A.sub.7 are parallel to the rotation axes A.sub.1 and A.sub.2.

(17) Referring to FIG. 1, both blades 51, 53 are in the inactive positions κ.sub.1, κ.sub.3 along the cutting direction T.sub.c. The direction T.sub.c makes an angle α.sub.1 with the direction passing through the rotation axes A.sub.1 and A.sub.2. This angle as well as the inactive positions κ.sub.1, κ.sub.3 along the cutting direction T.sub.c are determined by the angular orientation of the control lever 61, which is itself determined by the retracted position of the cylinder rod 67.

(18) Referring to FIG. 2, both blades 51, 53 have displaced into the active positions κ.sub.2, κ.sub.4 along the cutting direction T.sub.c. The direction T.sub.c makes an angle α.sub.2 with the direction passing through the axes of rotation A.sub.1 and A.sub.2. This angle as well as the active positions κ.sub.2, κ.sub.4 along the cutting direction T.sub.c are determined by the angular orientation of the control lever 61, which in turn is determined by the extended position of the cylinder rod 67.

(19) In either of the angles α.sub.1, α.sub.2 taken by the cutting direction T.sub.c, the blades 51, 53 remain aligned along said direction, which is ensured by the sliding connecting means 68.

(20) Referring to FIGS. 3 and 5, the first and second blades 51, 53 are in their inactive positions κ.sub.1, κ.sub.3 along the cutting direction T.sub.c. The apex of the cutting angle ϕ is in an initial position S.sub.1 determined by said inactive positions κ.sub.1, κ.sub.3 in which the cutting edges 52, 54 of the bevels 56, 58 are not overlapped.

(21) Referring to FIGS. 4 and 6, the first and second blades 51, 53 have displaced into their active positions κ.sub.2, κ.sub.4 in the cutting direction T.sub.c. The apex of the cutting angle ϕ is in an end position S.sub.2 determined by said active positions κ.sub.2, κ.sub.4 in which the cutting edges 52, 54 of the bevels 56, 58 are overlapped.

(22) Between the inactive positions κ.sub.1, κ.sub.3 and active positions κ.sub.2, κ.sub.4, the apex S.sub.1, S.sub.2 of the cutting angle ϕ has propagated as the overlapping of the cutting edges 52, 54 has increased.

(23) The cutting edges 52, 54 are rectilinear and form a constant cutting angle ϕ, from the inactive positions κ.sub.1, κ.sub.3 to the active positions κ.sub.2. The bisector of the cutting angle ϕ is perpendicular to the cutting direction T.sub.c. In FIGS. 5 and 6, the inactive positions κ.sub.1, κ.sub.3 and the active positions κ.sub.2, κ.sub.4 are advantageously chosen symmetrically with respect to the guiding plane P so that the bisector of the cutting angle ϕ is coincident with said plane P.

(24) The first blade 51 is fixed to a first blade holder 57. The second blade 53 is fixed to a second blade holder 59 by means of a part 55 pivoting relative to said second blade holder 59 around an axis 50 and pressed against the first blade holder 57 by an elastic return means to control the clearance necessary for the overlapping of the cutting edges 52, 54 of the blades 51, 53. The elastic return means is, for example, a spring mounted around a screw 4 passing through the intermediate part 55 to be screwed into the second blade holder 59, the spring being arranged between the screw head and the intermediate part. According to an embodiment variant, the second blade is elastically biased in abutment directly against the first blade, either flat or by its cutting edge, for example according to the mounting principle described in the above-mentioned application WO 2017/072421.

(25) A second embodiment of the invention differs from the previous one in that only one of the two cutting tools is movable in translation along the cutting direction, the other tool being in a fixed position along said direction. Document WO 2008/132301 describes, for example, a movable blade coming, in the active position, into abutment against a counter-tool which is fixed in the cutting direction and is made of a bar of elastomeric material.

(26) The application head according to the invention is specially designed to be installed in a fiber placement machine for the production of composite material parts. It is completed, FIGS. 7 to 10, for each fiber, by a clamping system 7 and rerouting means 9.

(27) The clamping system 7 comprises first and second clamping tools 71, 73 movable along a clamping direction T.sub.b between two inactive positions and two active positions in which they abut against each other. A control means 8 is able to displace said first and second clamping tools 71, 73 in translation along the clamping direction T.sub.b. It comprises a cylinder 81 actuating a cylinder rod 83 cooperating with the first and second clamping tools 71, 73 by means of a transmission cone 85.

(28) Said clamping tools 71, 73 are movable together in translation between an initial clamping position β.sub.1 and a final clamping position β.sub.2 representing a variation in distance along the guiding plane P. They are displaced by a control means 10 comprising a cylinder 101 actuating a cylinder rod 103 able to displace the cylinder 81 of the control means 8.

(29) Stripper means 41, 43 are fixed in relation to the structure used as support for the mounting of the application head. The inactive positions of the first and second clamping tools 71, 73 are set back along the clamping direction T.sub.b with respect to the fixed positions of the stripper means 41, 43. The stripper means 41, 43 are movable with said clamping tools 71, 73 in translation along the guiding plane and controlled in displacement by said control means 10.

(30) The rerouting means 9 comprise a first roller 91 and a second roller 93 whose rotation axis 95 and 97 are aligned along a direction R away from the rotation axis 11 of application roller 1. The rerouting means 9 have a fixed position with respect to the application roller 1, between the blades 51, 53 on the one hand and said clamping tools 71, 73 on the other hand.

(31) Referring to FIG. 7, both blades 51, 53 are in their initial position ψ.sub.1 in which the distance along the guiding plane P between the cutting direction T.sub.c and the fixed position of rerouting means is equal to D.sub.1. Similarly, the two clamping tools 71, 73 are in their initial position β.sub.1 in which the distance along the guiding plane P between the clamping direction T.sub.b and the fixed position of the rerouting means is equal to Δ.sub.1. Along the cutting direction T.sub.c, the blades 51, 53 are in their inactive positions κ.sub.1, κ.sub.3 (FIG. 1). Along the clamping direction T.sub.b, the clamping tools 71, 73 are in their inactive positions.

(32) Referring to FIG. 8, the two blades 51, 53 have displaced together to their final position ψ.sub.2 in which the distance along the guiding plane P between the cutting direction T.sub.c and the fixed position of the rerouting means is equal to D.sub.2. The two clamping tools 71, 73 have remained in the initial position β.sub.1 shown in FIG. 7. Along the cutting direction T.sub.c, the blades 51, 53 have displaced into their active positions κ.sub.2, κ.sub.4 (FIG. 2). Along the clamping direction T.sub.b, the clamping tools 71, 73 have displaced into their active positions.

(33) Referring to FIG. 9, both blades 51, 53 have remained in their final position ψ.sub.2 as shown in FIG. 8. The two clamping tools 71, 73 have displaced together into their final position β.sub.2 for which the distance along the guiding plane between the clamping direction T.sub.b and the fixed position of the rerouting means is equal to Δ.sub.2.

(34) Referring to FIG. 10, the two blades 51, 53 have displaced together to their initial position ψ.sub.1 shown in FIG. 7. The two clamping tools 71, 73 have remained in their final position β.sub.2 as shown in FIG. 9. Along the cutting direction T.sub.c, the blades 51, 53 have displaced to their inactive positions κ.sub.1, κ.sub.3.

(35) The initial distances D.sub.1 and Δ.sub.1 are smaller than the final distances D.sub.2 and Δ.sub.2. Thus, the initial and final cutting positions ψ.sub.1, ψ.sub.2 represent a positive variation of distance D.sub.2-D.sub.1 along the guiding plane P and the initial and final clamping position β.sub.1, β.sub.2 represent a positive variation of distance Δ.sub.2-Δ.sub.1 along the guiding plane P.

(36) It is important to note that the direction R of the rerouting means is an arbitrary reference for the distances D.sub.1, Δ.sub.1, D.sub.2 and Δ.sub.2. The direction perpendicular to the guiding plane P and passing through axis 11 of application roller 1 is another arbitrary reference for locating said distances. It is sufficient that the reference direction is perpendicular to the guiding plane and has a fixed position in the application head.

(37) A fiber 2 is applied to a substrate (not shown) by the application roller 1 as the application head displaces relative to the substrate. The fiber is guided by the guiding means in the guiding plane P.

(38) A “cut on the fly” operation comprises the following steps: first step: FIG. 7, during layup, the fiber 2 circulates freely through the cutting tools formed by the blades 51, 53 and the clamping tools 71, 73. The inactive positions κ.sub.1, κ.sub.3 of the cutting tools define a rest state along the cutting direction T.sub.c. Likewise, the inactive positions of the clamping tools define a rest state along the clamping direction T.sub.b. second step: FIG. 8, the fiber 2 is cut by the blades 51, 53 and clamped by the clamping tools 71, 73. The active positions κ.sub.2, κ.sub.4 of the blades define an active state along the cutting direction T.sub.c. Likewise, the active positions of the clamping tools define an active state in the clamping direction T.sub.b.

(39) Between the first and second steps, the blades 51, 53 have undergone, along the guiding plane P, the positive variation in distance D.sub.2-D.sub.1. This variation makes it possible to displace the cutting direction T.sub.c at the same time as fiber 2 and thus leads to cancelling the inclination of the cut end of the fiber.

(40) The inactive positions κ.sub.1, κ.sub.3 along the cutting direction T.sub.c are symmetrical with respect to the guiding plane P and the blades 51, 53 are displaced towards their active positions κ.sub.2, κ.sub.4 at the same translation speed. Thus it is possible to cut the fiber 2 “in the middle”, that is without deviation from the guiding plane P. third step: FIG. 9, blades 51, 53 remain in the active state. Similarly, the clamping tools 71, 73 remain in the active state.

(41) Between the second and third steps, the clamping tools 71, 73 have undergone the positive variation in distance Δ.sub.2-Δ.sub.1 along the guiding plane P. This variation makes it possible to displace the cut and clamped fiber 2 in the opposite direction to the travel direction imposed by the rotation direction of the application roller 1. fourth step: FIG. 10, the blades 51, 53 are again in the resting state. The clamping tools 71, 73 remain in the active state.

(42) Between the third and fourth steps, the blades 51, 53 have undergone, along the guiding plane P, the negative variation in distance D.sub.1-D.sub.2. The variation in distance Δ.sub.2-Δ.sub.1 of the clamping tools 71, 73 is chosen to be greater than the variation of distance D.sub.2-D.sub.1 of the cutting tools to allow the latter to return to the distance D.sub.1 of the rerouting means 9 without the risk of coming into contact with the fiber 2. fifth step: the clamping tools 71, 73 are again in the resting state. The blades 51, 53 remain in the resting state. The fiber 2 circulates freely after it has been rerouted by the rerouting means.

(43) Between the fifth step and the first step of the next “on-the-fly” cut, the clamping tools 71, 73 are subjected to the negative variation in distance Δ.sub.1-Δ.sub.2 along the guiding plane P.

(44) The “on-the-fly” cut operation described above can be carried out with an application head in which only one of the two clamping tools is movable in translation along the clamping direction, the other tool being in a fixed position along said direction. Document WO 2008/132301 or EP 846551 describes a movable jaw which, in the active position, abuts against a counter-tool which is fixed along the clamping direction.