FR3055576A1 - CUTTING DEVICE FOR FIBER PLACEMENT HEAD - Google Patents

Abstract

Device (300) for cutting at least one fiber web (3), the device comprising: - a chassis (9), the fiber web being intended to circulate in a running direction (D) with respect to the chassis, - A cutting blade (2) fixedly mounted relative to the frame and provided with at least one cutting edge (21), - at least one movable element (4) movable relative to the frame in a movement having at least one component perpendicular to the running direction, the movable member having a non-cutting surface (41) for urging the fiber web against the cutting edge during said movement to sever the fiber web, and adapted to strike the cutting edge.

Description

© Publication no .: 3,055,576 (to be used only for reproduction orders)

©) National registration number: 16 58186 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © Int Cl ⁸ : B 29 C 70/38 (2017.01), B 26 D 1/02, 1/45

A1 PATENT APPLICATION

©) Date of filing: 02.09.16. © Applicant (s): FIVES MACHINING Société ano- (© Priority: nyme - FR. @ Inventor (s): STEIN NICOLAS and VEYSSET VIC- TOR-PIERRE. (43) Date of public availability of the request: 09.03.18 Bulletin 18/10. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ©) Holder (s): FIVES MACHINING Société anonyme. related: ©) Extension request (s): (© Agent (s): LAVOIX.

Pty CUTTING DEVICE FOR FIBER PLACEMENT HEAD.

FR 3 055 576 - A1 ff) Device (300) for cutting at least one strip of fibers (3), the device comprising:

- a frame (9), the strip of fibers being intended to circulate in a running direction (D) relative to the frame,

- a cutting blade (2) mounted fixed relative to the chassis and provided with at least one cutting edge (21),

- at least one movable element (4), movable relative to the frame according to a movement having at least one component perpendicular to the direction of travel, the movable element having a non-sharp surface (41) intended to push the strip of fibers against the cutting edge during said movement to cut the strip of fibers, and adapted to strike the cutting edge.

Cutting device for fiber placement head

The invention relates to the technical field of composite fiber placement machines comprising a head for applying fiber bands for producing parts made of composite materials. The present invention relates more particularly to a fiber strip cutting device used in the application heads of said fiber placement machines.

A composite material is an assembly of at least two immiscible components, but having a high penetration capacity, whose properties complement each other. In the aeronautical and automotive fields, composite materials are commonly used composed of an assembly of fibers and resin. For the production of parts, strips or strips already made of fibers and resin are used and stored in a roll. Industrialists use these rolls of fiber tape to manufacture larger pieces by assembling ends of fiber strips, of different dimensions, on top of each other.

To automate this manufacturing, for example, robots or gantries are used on which fiber placement heads are installed. The term "fibers" can also be used in the technical field to designate strips of fibers. To allow routing and placing the ends of the fiber strips in the right place on the workpiece, the fiber placement head has one or more cutting tools as close as possible to the application on the workpiece.

In this area, a number of cutting techniques are known which have been developed by different suppliers of fiber placement machines. The goals sought by these techniques are cutting precision and reducing the size of the cutting system for good agility of the fiber placement head. The economic component, on the other hand, is not dealt with by current market techniques.

In particular, systems are known for cutting strips of fibers using cutting blades for each strip of fibers to be cut. These blades are mobile and strike the strips of fibers on anvils to cut them. The blades are changed regularly to ensure a good cut, because the edge of the blades dulls quickly on the anvils during use. Their replacements result in financial losses due to the unavailability of the fiber placement machine for the production of parts. In addition, the blades are more or less costly wear elements.

Another known technique is to use rotary blades to improve the cut and the life of the blades in the cutting tools. This technique has the disadvantage of being difficult to implement in a reduced space and requires the installation of a special clamp to hold the strip on the blade during cutting.

Thus, an object of the present invention is in particular to propose a device improving the cutting function of the strips of fibers, while ensuring economic optimization of the wearing elements of said device.

To this end, the invention relates to a device for cutting at least one strip of fibers, the device comprising:

- a frame, the strip of fibers being intended to flow in a direction of travel relative to the frame, for example on the frame;

- a cutting blade mounted fixed relative to the chassis and provided with at least one cutting edge; and

- At least one movable element, movable relative to the frame according to a movement having at least one component perpendicular to the direction of travel, the movable element having a non-cutting surface intended to push the strip of fibers against the cutting edge during said movement to cut the strip of fibers, and adapted to strike the cutting edge.

According to particular embodiments, the device comprises one or more of the following characteristics, taken alone or in any technically possible combination:

the cutting blade extends in a plane, the direction of travel forming with the plane an angle less than or equal to 90 °, the mcbile element describing a circular trajectory around an axis during said movement, the surface forming preferably an angle substantially equal to 90 ° with the plane when the surface strikes the cutting edge;

- The chassis comprises a strip support located upstream of the cutting blade in the running direction and on which the fiber strip is intended to slide, the strip support being able to straighten the fiber strip after cutting;

- The surface is adapted to block the strip of fibers on the strip support relative to the frame;

the movement of the mobile element comprises a linear sliding with respect to the cutting blade, the mobile element defining an opening in which the strip of fibers is intended to circulate, the strip of fibers being cut when the surface passes under the sharp edge;

- The mobile element is adapted to support the strip of fibers at the opening at least at the start of said movement;

- The device comprises a mechanical element for moving the mobile element according to said movement;

the movable element comprises an upper part and a lower part which are movable with respect to each other and which define at least partially the opening, the strip of fibers being intended to be pinched between the upper part and the lower part before being cut; and

- The device is adapted to further cut at least one second strip of fibers, the device comprising at least one second movable element, movable relative to the frame according to a movement having at least one component perpendicular to the direction of travel, the second element mobile being intended to push the second strip of fibers against the cutting edge during said movement to cut the second strip of fibers, and being adapted to strike the cutting edge.

The invention also relates to an assembly of a device as described above and of at least one strip of fibers, the strip of fibers circulating in the direction of travel relative to the frame, the surface pushing the strip of fibers against the edge. cutting during said movement to cut the strip of fibers, and striking the cutting edge.

The invention also relates to a process for cutting at least one strip of fibers, the process comprising the following steps:

circulation of the strip of fibers with respect to a chassis, preferably on the chassis, in a running direction,

- supply of a cutting blade mounted fixed on the chassis and provided with at least one cutting edge, and

displacement of at least one movable element relative to the chassis in a movement having at least one component perpendicular to the direction of travel, the movable element having a non-cutting surface pushing the strip of fibers against the cutting edge during said movement , severing the strip of fibers, and striking the cutting edge.

The characteristics and advantages of the invention will appear on reading the description which follows, given only by way of example, and not limiting, with reference to the accompanying drawings, in which:

- Figure 1 is a schematic view, in section, of a device according to a first embodiment of the invention;

- Figure 2 is a schematic representation, in perspective, of a variant of the device shown in Figure 1;

- Figure 3 is a sectional view of a device according to a second embodiment of the invention;

- Figure 4 is a sectional view of a device according to a third embodiment of the invention; and

FIG. 5 is a perspective and enlarged view of the device shown in FIG. 4, the movable elements however being a variant of that shown in FIG. 4.

The examples of embodiment and implementation of the invention given in this description relate to the manufacture of composite parts by placing fibers in the aeronautical sector, but are in no way limiting. The invention can indeed be applied to all industrial sectors requiring the cutting of a strip of fibers for gluing them in order to produce parts. The invention applies, for example, to the automotive sector.

Referring to Figure 1, a device 1 is described according to a first embodiment of the invention.

The device 1 comprises a frame 9 on which are fixed a cutting blade 2 and a band support 5.

A strip of fibers 3 runs on the strip support 5 in a running direction D in a running position. The fiber strip 3 passes over or in front of the cutting blade 2, and slides on the strip support 5.

In the present application, "top >> and" bottom >>, as well as "above" and "below", must be understood in relation to the top and bottom of the figure in which it is made reference.

The band support 5 is advantageously flexible and makes it possible to position the fiber band 3 above the chassis 9 so that it can resume its path in the direction of travel D without striking said chassis 9 or the blade 2, even after the cup.

A mobile element 4 is positioned above or opposite a cutting edge 21 of the cutting blade 2, the strip of fibers 3 passing between the cutting blade 2 and the mobile element 4. This element mobile 4 is composed of a body 40 and an anvil 42.

The anvil 42 has at the cutting edge 21 a surface 41 which covers the width of the strip of fibers 3 at the level of the cutting blade 2 and can come into contact with the strip support 5 during the cutting phases of the strip of fibers 3.

The surface 41 is not sharp. It can be flat, concave or convex.

The cutting blade 2 is fixed to the chassis 9 by a locking device 6, in particular a screw or any other mechanical locking device (spring, magnets, etc.). Advantageously, the cutting blade 2 has two cutting edges 21 and 21 ′ opposite one another. The cutting blade 2 extends along a plane Z perpendicular to the direction of travel D in this example.

When the cutting edge 21 is dulled by the repeated striking of the anvil 42, it is possible to change the direction of the cutting blade 2 to present the second cutting edge 21 ′ in good condition to the anvil.

To further increase the life of the cutting blade 2, according to a particular embodiment of the invention, the cutting blade 2 is moved in a transverse direction T by at least one width of fiber strip 3, so to present a non-blunt part of the cutting edge 21, 21 ′ at the level of the striking of the anvil 42. Thus the blunt part of the cutting blade 2 is no longer under the strip of fibers 3 to be cut.

The transverse direction T is for example orthogonal to the direction of travel D.

The anvil 42 is made of a material compatible with the cutting of the fiber strip 3. It is a wearing part, but it is less expensive and more durable than the cutting blade 2. In an alternative embodiment of the invention, the anvil 42 can also be used in at least two directions to extend its service life.

One of the advantages of the movable element 4 carrying the anvil 42 is to obtain a mass or hammer blow effect which improves the speed of cutting of the fiber strip 3.

The mobile element 4 is actuated directly or indirectly by mechanical element 7, for example a piston, which gives it a movement in the direction of the cutting blade 2, from an initial position shown in FIG. 1. The movement has a component perpendicular to the direction of travel D. The movement is for example substantially perpendicular to the direction of travel. The movement is advantageously perpendicular to the cutting edge 21.

The anvil 42 strikes the strip of fibers 3 and pushes it against the cutting edge 21 of the blade 2. According to a particular embodiment of the invention, if the anvil 42 is wide enough in the direction of travel D, it can also wedge the fiber strip 3 against the blade support 5 and then continue its journey to the cutting edge 21. The fiber strip 3 is temporarily stopped during cutting.

The flexibility of the band support 5 makes it possible to raise the fiber band 3 above the cutting blade 2 when the movable element 4 rises to the initial position.

With reference to FIG. 2, a device 100 constituting a variant of the device 1 shown in FIG. 1 is described.

The device 100 is similar to the device 1. It differs only in that it comprises three tape supports 5, 5 ’, 5” allowing to support three strips of fibers 3, 3 ’, 3” to be cut independently. The device 100 also includes three mobile elements 4 (not shown).

FIG. 3 represents a device 200 according to a second embodiment of the invention.

The device 200 is similar to the device 1 shown in FIG. 1. Only the differences will be described below.

The actuator of the mobile element 4 is offset to save space at the level of the application head of the fiber placement machine. For this, the mobile element 4 is mounted on a mechanical element 7, such as a connecting rod.

The connecting rod 7 is rotated about an axis 71 by at least one actuator. This configuration allows an anvil 42 to be described as an arc of a circle Γ.

The cutting blade 2 is inclined relative to the direction of travel by an angle a less than or equal to 90 °.

The cutting blade 2 is struck by the surface 41 of the anvil 42 at an angle β substantially equal to 90 ° when the connecting rod 7 pivots around the axis 71.

Thanks to this movement, the surface 41 pushes the strip of fibers 3 towards the cutting blade 2 which cuts it in contact with its cutting edge 21. In a particular embodiment of the invention, the surface 41 can wedge the fiber strip 3 against the strip support 5 in the same cutting movement.

When the anvil 42 is raised, the band support 5 goes up the fiber band 3 in the running position.

Locking devices 6 hold the cutting blade 2 relative to the chassis 9.

According to a particular embodiment (FIG. 2), the cutting blade 2 cuts several strips of fibers thanks to several mobile elements 4 and several connecting rods 7.

Figures 4 and 5 show a device 300 according to a third embodiment of the invention. The device 300 is similar to the device 200 shown in FIG. 3. Only the differences will be described below.

The device 300 comprises for example two mobile elements 4, 4 ′ (FIG. 5) making it possible to cut two strips of fibers 3 on the same cutting blade 2. The mobile elements 4, 4 ’are driven by two connecting rods 7, 7’. The mobile elements 4, 4 ’being analogous to each other, only the mobile element 4 and its operation will be described.

The connecting rod 7 is actuated by at least one piston (not shown) to pivot around its axis 71.

The mobile element 4 is traversing and lets the fiber strip 3 pass through an opening 44. The mobile element 4 slides along the cutting blade 2, the cutting edge 21 of which is in contact with the mobile element 4. L mobile element 4 has a movement substantially perpendicular to the direction of travel D.

The cutting blade 2 is held in position by holding elements 6 to guarantee contact of the cutting edge 21 with the movable element 4.

The opening 44 includes a surface 41 which is opposite the cutting blade 2 with respect to the fiber strip 3 engaged in the opening. The opening 44 is advantageously higher on the entry side of the fiber strip 3 in the direction of travel D, to avoid jamming of the fiber strip between the frame 9 and the movable element 4 during sliding.

As a variant (not shown), the frame 9 is chamfered on the entry side of the fiber strips 3 in the direction of travel D to achieve the same result, that is to say to avoid jamming of the fiber strip 3 between the chassis 9 and the movable element

4.

The upper part of the outlet orifice of the opening 44 can take different geometries to optimize the cutting of the strip of fibers 3. It can for example bring the strip of fibers 3 into contact with the cutting blade 2 over its whole width in the transverse direction T simultaneously, or start with one side of the fiber strip or start with the transverse ends of the fiber strip 3 to go towards the center of the fiber strip.

The connecting rod 7 cooperates with the movable element 4, directly or by means of a mechanical part 72 in order to limit friction on the movable element 4, for example a bearing. The rotational movement of the connecting rod 7 around the axis 71 is thus transformed into movement of the mobile element 4, here a rectilinear translation.

The top of the mobile element 4, which is in contact for example with the bearing 72, is advantageously inclined relative to the direction of travel D so that the connecting rod 7 can exert a force towards the cutting blade 2 guaranteeing better contact of the cutting edge 21 with the movable element 4.

When the connecting rod 7 is actuated by an actuator, the connecting rod pivots about the axis 71 and pushes the movable element 4 downwards, in the direction of the chassis 9. The surface 41 comes into contact with the fiber strip 3 and pushes it towards the cutting edge 21 of the cutting blade 2 causing its cutting by guillotine effect.

When the connecting rod 7 returns to its initial position, the mobile element 4 rises and assumes the role of band support to reposition the fiber band 3 in the running position.

The mobile element 4 can be raised in different ways, in particular by the action of a spring 8 located under the mobile element 4 or by a connection between the mobile element 4 and the connecting rod 7.

According to a variant of the device 300 shown only in FIG. 5, the mobile elements 4, 4 ’are in at least two parts.

An upper part 45 and a lower part 46 delimit the opening 44. The upper part 45 and the lower part 46 are movable towards one another, so that, when pressure is exerted on the upper part 45 of the movable element 4 by the connecting rod 7, the parts close the opening 44 and block the strip of fibers 3. The movable member 4 continues to descend, driving the strip of fibers 3 on the cutting edge 21 of the cutting blade 2 to obtain the shearing by guillotine effect.

When the connecting rod 7 rises, the movable element 4 rises and the two parts separate to define the opening 44 again. The upper part 45 and the lower part 46 can slide one inside the other to achieve this movement of towards each other, or make any other construction allowing the opening 44 to be closed on the fiber strip 3 when the connecting rod 7 actuates the movable element 4.

Thanks to the characteristics described above, the devices 1, 100 and 200, as well as their variants, improve the cutting function of the strips of fibers and have a reduced bulk, while ensuring an economic optimization of the wearing elements of said device.

The club effect, provided by the movable element 4, is greater when it is the club which moves, resulting in a sharper and faster cutting of the strip of fibers 3.

The use of a single cutting blade 2 to cut several strips of fiber with several moving elements 4 has the advantage of facilitating maintenance and being more economical to purchase. Blade 2 can be replaced or turned in a single operation, allowing the fiber placement machine to return to service more quickly than using a multitude of blades.

Claims (11)

1. - Device (1; 100; 200; 300) for cutting at least one strip of fibers (3), the device (1; 100; 200; 300) comprising: a chassis (9), the strip of fibers (3) being intended to flow in a direction of travel (D) relative to the chassis (9), for example on the chassis (9), - a cutting blade (2) fixedly mounted relative to the frame (9) and provided with at least one cutting edge (21), and - at least one movable element (4), movable relative to the frame (9) according to a movement having at least one component perpendicular to the direction of travel (D), the movable element (4) having a surface (41) not sharp intended to push the strip of fibers (3) against the cutting edge (21) during said movement to cut the strip of fibers (3), and adapted to strike the cutting edge (21). 2. - Device (200) according to claim 1, wherein the cutting blade (2) extends in a plane (Z), the direction of travel (D) forming with the plane (Z) an angle (a) less than or equal to 90 °, the movable element (4) deflecting a circular trajectory (Γ) around an axis (71) during said movement, the surface (41) preferably forming an angle (P) substantially equal to 90 ° with the plane (Z) when on the surface (41) strikes the cutting edge (21). 3. - Device (1; 100; 200; 300) according to claim 1 or 2, wherein the frame (9) comprises a band support (4; 5) located upstream of the cutting blade (2) according to the direction of travel (D) and on which the fiber strip (3) is intended to slide, the strip support (5) being able to straighten the fiber strip (3) after cutting. 4. - Device (1; 100; 200; 300) according to any one of claims 1 to 3, in which the surface (41) is adapted to block the strip of fibers (3) on the strip support (4; 5) relative to the chassis (9). 5. - Device (300) according to claim 1, in which the movement of the mobile element (4) comprises a linear sliding with respect to the cutting blade (2), the mobile element (4) defining an opening ( 44) in which the strip of fibers (3) is intended to flow, the strip of fibers (3) being severed when the surface (41) passes under the cutting edge (21). 6. - Device (300) according to claim 5, wherein the movable element (4) is adapted to support the strip of fibers (3) at the opening (44) at least at the start of said movement. 7. - Device (1; 100; 200; 300) according to any one of claims 1 to 6, further comprising a mechanical element (7) for moving the mobile element (4) according to said movement. 8. - Device (1; 300) according to claim 7, wherein the movable element (4) comprises a high part (45) and a low part (46) movable with respect to each other and defining at less partially the opening (44), the strip of fibers (3) being intended to be pinched between the upper part (45) and the lower part (46) before being cut. 9. - Device (100; 200; 300) according to any one of the preceding claims, suitable for further cutting at least one second strip of fibers (3 '), the device (100; 200; 300) comprising at least one second movable element (4 '), movable relative to the frame (9) according to a movement having at least one component perpendicular to the direction of travel (D), the second movable element (4') being intended to push the second strip of fibers (3 ') against the cutting edge (21) during said movement to cut the second strip of fibers (3'), and being adapted to strike the cutting edge (21). 10. - assembly of a device (1; 100; 200; 300) according to any one of claims 1 to 9 and of at least one strip of fibers (3), the strip of fibers (3) flowing along the direction of travel (D) relative to the frame (9), the surface (41) pushing the strip of fibers (3) against the cutting edge (21) during said movement to cut the strip of fibers (3), and striking the cutting edge (21). 11. - Method for cutting at least one strip of fibers (3), the method comprising the following steps: - circulation of the fiber strip (3) relative to a frame (9), preferably on the frame (9), in a direction of travel (D), - supply of a cutting blade (2) fixedly mounted on the chassis (9) and provided with at least one cutting edge (21), and - displacement of at least one mobile element (4) relative to the frame (9) according to a movement having at least one component perpendicular to the direction of travel (D), the mobile element (4) having a surface (41) non-cutting pushing the strip of fibers (3) against the cutting edge (21) during said movement, cutting the strip of fibers (3), and striking the cutting edge (21). 1/5