EP1045746A1

EP1045746A1 - Automatic cutting of pieces in a sheet material

Info

Publication number: EP1045746A1
Application number: EP99942987A
Authority: EP
Inventors: Didier Chabirand Garconnet; Thierry Badie
Original assignee: Lectra Systemes SA; Lectra SA
Current assignee: Lectra SA
Priority date: 1998-09-16
Filing date: 1999-09-16
Publication date: 2000-10-25
Anticipated expiration: 2019-09-16
Also published as: EP1045746B1; US6521074B1; ES2179673T3; US20030121610A1; FR2783191B1; WO2000015397A1; FR2783191A1; DE69902140D1; US7024976B2; DE69902140T2

Abstract

The invention concerns an installation cutting out pieces in a sheet material, comprising a cutting table (12) receiving the sheet material (30) from a loading station (12) and a station (16) for unloading cut out pieces. A flexible sealing film (32) is brought onto the sheet material upstream of the cutting table and is applied by causing a depression at the cutting table surface. After cutting, at least a skeleton (32)' of the sealing film is detached at the downstream end of the cutting table to be recovered. The recovery is carried out by automatic winding outside the unloading station, by placing clips on the sealing film astride on the cutting lines, or by suction of fragments of the sealing film using a rotary element pressing on the sheet material.

Description

Title of invention

Automatic cutting of parts in sheet material

Field of the Invention The invention relates to a method and an installation for the automatic cutting of parts of predetermined shapes from sheet material.

A particular field of application of the invention is the automatic cutting of parts from plies of textile material, in particular in the clothing industry. The invention is also applicable to the cutting of technical textiles in industrial applications, and to the cutting of nonwoven materials, such as leather.

BACKGROUND OF THE INVENTION A well known method for cutting parts from flexible sheet material is to bring the sheet material onto a table in a cutting area, either in a single ply or in several overlapping plies forming a mattress, and to cut pieces in accordance with a predetermined placement by means of a tool which penetrates into the material while the sheet material is held on the table by vacuum, with the application of a flexible sealing film on the surface of the sheet material. The vacuum is obtained by suction through the surface of the table. The tool is a knife animated by a vertical vibratory movement or a circular blade whose movement relative to the table is controlled in order to cut the pieces having the desired shapes, and at the locations on the surface of the sheet material defined by the pre-established placement. The tool cuts not only the sheet material but also the sealing film applied to it.

Downstream of the cutting area is an unloading area where the pieces cut from the sheet material are recovered. Each piece cut in a single fold, or each stack of pieces (or "log") cut in a mattress, is surmounted by a part of the same shape cut in the sealing film. The cut pieces or logs, possibly always provided with the part of the corresponding sealing film on which identification information can be carried, are taken from the unloading area. to be directed or temporarily stored for later use.

The presence in the unloading area of the skeletons of the sheet material and of the sealing film poses various problems. By skeletons is meant here the falls of the folds or mattresses of sheet material and sealing film having the shape complementary to that of all of the cut parts. Indeed, these falls clutter the unloading area and must be removed by an operator. In addition, the presence of falls can complicate the identification of the parts to be unloaded, all the more so when at least some of the parts are difficult to distinguish from falls.

Subject and summary of the invention

The invention aims to remedy the difficulties mentioned above and, according to one of its aspects, proposes for this purpose an automatic cutting process of sheet material of the type comprising the supply of at least one ply of material in sheet on a table in a cutting area, holding the sheet material on the table by vacuum, applying a sealing film to the surface of the sheet material, cutting pieces of predetermined shapes at by means of a tool passing through the sealing film and the sheet material, and the removal of cut pieces downstream from the table, process in which at least the skeleton of the sealing film is deviated from the path of the material sheet in a downstream end area of the table to be retrieved automatically, separately from the cut pieces.

According to a first embodiment, at least the skeleton of the sealing film is recovered by automatic rewinding. The rewinding can be carried out by calling on a mandrel at a tangential speed controlled by the speed of movement of the sheet material on the table.

Advantageously, the cutting of the parts is carried out while preserving the integrity of the skeleton, so that it is automatically recovered continuously. If necessary, the integrity of the skeleton could be restored by depositing fasteners, for example located on the surface of the sealing film. Thus, the skeleton of the sealing film is absent from the unloading zone, reducing the bulk thereof.

The absence of a film skeleton can make it easier to identify the cut pieces or logs, since these are the only parts of the sheet material which remain covered by the sealing film in the unloading area, insofar as the separation between the skeleton and the cut parts of the sealing film is well done. This separation can be facilitated by spreading the sealing film as best as possible so that it is stretched over the surface of the sheet material during cutting.

In a variant of the first embodiment of the invention, the skeleton of the sealing film is removed and recovered with at least some of the cut parts of the film. To this end, after cutting a part, the connection between the cut part of the sealing film and the skeleton can be re-established by means of fasteners deposited or formed on the film in a localized or continuous fashion along the cutting lines. . One can then have a partially or completely reconstituted sealing film capable of being reused.

According to a second embodiment, fragments of the sealing film formed by the skeleton and parts of the film cut with the parts are removed by suction from the path of the sheet material and then discharged.

Preferably, the wire fragments are removed by means of a movable member adjacent to the path of the sheet material. Advantageously, the movable member is rotated by contact with the sheet material and advances therefrom. As a variant, the movable member can be driven in rotation by means of a possibly disengageable device, associated with an independent motorization or driven in synchronism with means for moving the sheet material on the table.

Advantageously still, a rotary movable member is used comprising several sectors, and a vacuum is established in each sector during the movement of the latter between the proximity of the path of the sheet material and a zone for evacuating film fragments. An overpressure can then be established in each sector when it reaches the evacuation zone. The film fragments can be discharged by depositing them in a receptacle situated above the path of the sheet material and extracting the receptacle or by being brought to a discharge duct.

According to another aspect of the invention, it relates to an installation for automatic cutting of sheet material allowing the implementation of the above method.

To this end, an installation of the type is proposed comprising a cutting table, a station for loading material in sheet to be cut at an upstream end of the cutting table, a station for unloading cut pieces at a downstream end of the cutting table, means for establishing a vacuum on the surface of the cutting table, and means for supplying a flexible sealing film in the vicinity of the upstream end of the cutting table, installation wherein means are further provided for separating at least one skeleton of sealing film in the vicinity of the downstream end of the cutting table and for automatically recovering it from the unloading station for cut pieces.

According to a first embodiment, the installation comprises means for automatically winding at least the skeleton of the sealing film. The automatic winding means can be mechanically connected to drive means ensuring the advance of sheet material on the cutting table, so as to control the tangential winding speed to the speed of advance of sheet material . As a variant, the winding means comprise a motor controlled as a function of the speed of advance of sheet material on the cutting table, in order to control the tangential speed of winding at this speed of advance.

Means intended for depositing or forming attachments to the surface of a sealing film present on the cutting table can be provided. The means for depositing or forming fasteners are advantageously carried by a carriage also supporting a cutting tool can be provided. As a variant, the means for depositing or forming fasteners extend transversely with respect to the cutting table, at the downstream end thereof. According to a second embodiment, the installation comprises means for sampling by suction of film fragments sealing, in the vicinity of the downstream end of the cutting table, and means for removing fragments of film removed.

Advantageously, the suction withdrawal means comprise a rotary drum having several sectors which communicate with the outside through orifices opening on the surface of the drum, and means for depressurizing the sectors over part of their path in rotation between a location located near the plane of the cutting table and a location located near the means for removing film fragments. Brief description of the drawings

Other features and advantages of the invention will emerge on reading the description given below, by way of indication but not limitation, with reference to the appended drawings in which:

FIG. 1 is a very diagrammatic view in side elevation of an embodiment of a cutting installation according to the invention,

- Figure 2 is a top view of the installation of Figure 1,

- Figure 3 is a side elevational view showing in more detail the downstream end zone of the cutting table of the installation shown in Figure 1, - Figure 4 is a front view in the direction A of the figure

3,

- Figure 5 is a partial detail view of a carriage such as that of the installation of Figure 1, carrying a device for depositing localized fasteners, according to a first alternative embodiment of the installation of Figure 1 ,

FIG. 6 is a front elevation view of the carriage of FIG. 5,

- Figure 7 is a partial detail view of a carriage such as that of the installation of Figure 1, carrying a device for forming localized fasteners, according to a second alternative embodiment of the installation of Figure 1 ,

- Figure 8 is a partial detail view of a carriage such as that of the installation of Figure 1, carrying a device for forming continuous fasteners, according to a third alternative embodiment of the installation of Figure 1 , FIG. 9 is an elevation view illustrating a device for applying transverse adhesive tape according to a fourth alternative embodiment of the installation of FIG. 1,

FIG. 10 is a top view of the device for applying adhesive tape of FIG. 9,

FIG. 11 is an elevation view illustrating a device for forming transverse welding lines according to a fifth alternative embodiment of the installation of FIG. 1,

FIG. 12 is a top view of the device for forming welding lines of FIG. 11,

FIG. 13 is a schematic side elevation view of a second embodiment of a cutting installation according to the invention,

FIG. 14 is a partial top view of the installation of FIG. 13,

FIG. 15 is a detail view in side elevation on an enlarged scale of the sampling drum and of the receptacle for recovering film fragments from the installation of FIG. 13,

FIG. 16 a partial top view of the drum and of the receptacle of the installation of FIG. 13, in section along the line XVI-XVI of FIG. 15,

FIG. 17 is a cross-sectional view of the drum of FIG. 15,

FIG. 18 is a schematic side elevation view of an alternative embodiment of the installation of FIG. 13,

- Figure 19 is a partial top view of the installation of Figure 18, and

FIG. 20 is a partial detail view, on an enlarged scale, in side elevation and in section, of the sampling drum and means for evacuating the installation from FIG. 18.

Detailed description of preferred modes of the invention

Figures 1 and 2 show an automatic cutting installation of parts in sheet material, comprising a cutting station 10 located between a station 12 for loading sheet material to be cut and a station 16 for unloading parts cut from the material in sheet. The cutting station 10 comprises a cutting table 20 formed by the horizontal upper strand of an endless conveyor 22. This is housed, with the exception of its horizontal upper surface delimiting the table 20, inside d 'a box 24. Suction means such as one or more extractors 26 are arranged in the box in order to establish a vacuum there.

The conveyor 22 consists of blocks 22a having or forming between them passages making the interior of the box communicate with the surface of the table 20. The blocks 22a, for example made of plastic, have a base from which protrude a plurality of 'filiform elements. In this way, a cutting tool, such as a blade, can penetrate the surface of the table 20 and move horizontally in all directions without being damaged and without damaging the blocks 22a. A sheet material to be cut 30 is brought to the table 20.

The sheet material is typically a flexible material, for example a textile material, such as a fabric. It is brought to the table in the form of a single fold or, as in the example illustrated, in the form of a mattress 30 formed of a plurality of superimposed folds. The mattress 30 is for example formed on a quilting table 14 of the loading station, upstream of the cutting station 10, and is advanced on the table 20 in direction X by control of a drive motor 28 of the conveyor 22. Throughout the description, the terms "upstream" and "downstream" are used with reference to the direction of movement of the mattress 30 on the cutting table 20.

A flexible film 32 of airtight plastic, for example a polyethylene film, is drawn from a horizontal roller 34 situated at the level of the upstream end of the table 20, overhanging with respect thereto, and is placed on the mattress 30 in order to cover it completely. The roller 34 is supported at its ends by two uprights 36 fixed to the frame of the cutting station, on each side of the table 20. The uprights 36 also carry a horizontal deflection roller 40. The film 32 is applied against the surface of the mattress 30 by means of a roller 42 supported at its ends by two arms 44 articulated on the uprights 36. The cutting of the mattress 30 carried by the table 20 and covered with the sealing film 32 is carried out by means of a head cutting 50. The cutting head can be brought into any position above the table 20 by control of its horizontal movement parallel to the longitudinal direction X of the conveyor 22 and to the transverse direction Y perpendicular to X.

The cutting head 50 is mounted on a carriage 52 which is movable in the Y direction along a transverse beam 54, under the control of a motor 56. The beam 54 is supported at its ends along the longitudinal edges of the conveyor 22 and is driven in direction X by a motor 48. The drive of the carriage 52 can be carried out in a conventional manner by means of cables or, as illustrated, of worm screw 57. The drive of the beam 54 can also be produced by means of cables or endless screw or, as illustrated, by toothed wheels and racks 59, these being fixed on the upper longitudinal edges of the box 24.

The cutting head 50 carries a cutting blade 60 suspended vertically under a rotary plate 62. On the upper side, the plate 62 is coupled to a motor 64 by a connecting rod-crank system making it possible to print on the plate 62 and on the blade 60 a vertical reciprocating movement. The blade 60 is orientable under the control of a motor 66 coupled to the rotary plate 62. The motors ensuring the displacements in X, Y of the carriage carrying the cutting head above the cutting table, the alternating vertical movement of the cutting blade, and the orientation thereof are controlled by a computer 68. The latter also controls the advance of the conveyor 22 and the depression of the box 24 by which the mattress 30 covered by the waterproof film 32 is firmly held on the table 20.

An installation as described above is well known to those skilled in the art. Reference may for example be made to US patent document 3,848,490. The displacements of the cutting head in X, Y are controlled so as to cut parts in the mattress 30 according to a determined placement. The pieces are, for example, constituent elements of clothing and their placement is in particular carried out to minimize the loss of material. During cutting, the cutting blade is oriented so as to remain tangent or substantially tangent to the contour of the cut piece. When a mattress section 30 present on the table 20 has been cut, with the waterproof film 32, an advance of the conveyor 22 is controlled by the motor 28 to advance a new mattress section or a new mattress. It is also possible to carry out the advance of the mattress without interrupting the cutting, successive lengths of mattress being brought to the cutting table 20 as the cutting progresses. A process allowing the mattress to advance in masked time during cutting is described in French patent application FR 2 707 545.

According to the invention, means are provided in the vicinity of the downstream end of the cutting table 20 to separate at least the skeleton 32 'of the waterproof film, by deflecting it from the path of the cut mattress, in order to recover it.

In the embodiment illustrated in Figures 1 to 3, only the skeleton 32 'is separated, while the parts 32 "of waterproof film cut with the parts in the mattress 30 remain on these parts. The skeleton 32' is recovered by winding by being called on a mandrel 70 of horizontal axis parallel to the direction Y. For example, a mandrel is used on which a reel of sealed film was previously wound and which has been recovered after use of the complete film.

The mandrel 70 is supported at its ends in bearings carried by respective arms 72 fixed to the frame of the cutting station, on each side of the table 20. Between its horizontal path above the table 20 and the winding mandrel 70, the skeleton 32 'passes over a deflector 74 and a deflection roller 76. The deflector is a horizontal bar extending at least over the width of the table 20 and carried at its ends by plates 78 mounted on the arms 72 The position of the deflector 74 in the direction X and in height is adjustable in order to ensure that the separation of the skeleton 32 ′ with respect to the mattress takes place substantially at the desired location. The horizontal deflection roller 76 is mounted on the arms 72. In order to ensure good cutting of the parts 32 "of the waterproof film and their complete separation from the skeleton 32 ', it is desirable that the film 32 is correctly spread out and preferably stretched Also, the deflection roller 40 is given a curved shape, or "banana" shape, as is well known in the textile field for devices for spreading wires or cables.

The separation of the skeleton 32 "and its recovery outside the unloading station 16 makes it possible to prevent the unloading of the stacks of parts, or logs, cut from the mattress, are hampered by the skeleton of the film. The parts of the cut film 32 "can be unloaded with the corresponding logs, in particular when they carry identification information for the cut parts. The unloading station 16 comprises a table receiving the cut mattress. The table is for example constituted by the upper side of a conveyor 17 moved in synchronism with the conveyor 22. Between the conveyors 22 and 17, the mattress passes over a support 19 in the form of a comb. The winding of the skeleton 32 ′ on the mandrel 70 is preferably carried out by synchronism with the advance of the mattress 30 on the table 20.

In the embodiment of FIGS. 3 and 4, the control of the tangential winding speed on the mandrel to the speed of advance of the mattress is achieved by mechanical coupling and differential system between the motor 28 and the mandrel 70.

The conveyor 22 is moved by means of the motor 28 via a main chain 80. A gear train 82 takes up this main chain and transmits its movement to a return chain 84. This passes over a receiving pinion 86 which is positioned on the axis of rotation of the mandrel 70 and which is connected, by means of a torque limiter 88, to a lashing bar 90 on which the mandrel 70 is mounted. The connection between the torque limiter 88 and the lashing bar 90 is made by a drive bearing 92.

Alternatively, the enslavement of the winding speed on the mandrel 70 to the speed of advance of the mattress 30 on the table 20 can be achieved by electronic means, the mandrel then being provided with its own drive motor. This motor is controlled by the computer 68 from signals representative of the advance of the conveyor, for example supplied by a coded wheel associated with a roller on which the conveyor 22 passes.

In order to preserve the integrity of the skeleton 32 ′, it is necessary that the cuts made do not define lines going continuously from one edge to the other of the film. The parts can be placed in such a way as to exclude such a possibility. It is however possible and sometimes desirable to restore the integrity of the skeleton in cut areas by depositing or forming ties on the film 32, there or the skeleton. is cut. This can be achieved by depositing localized fasteners on the film before separation of the skeleton.

In the event that the location of the logs by labels deposited on the surfaces of the film parts 32 "cut with the pieces is not carried out, these film parts 32" can be secured to the skeleton in their original positions. This joining is carried out by the installation or formation of localized or continuous fasteners overlapping the outline of each part of film 32 "at several locations of this outline or all along this outline. In this way, the film 32 can be recovered almost in its entirety and can be reused despite the fact that its sealing may no longer be absolute when the fasteners are only located.

Different devices for fitting or forming fasteners can be used. Figures 5 and 6 schematically show a device 100 for depositing labels or self-adhesive pads 102, which is mounted on the carriage 52 supporting the cutting head, behind the cutting tool. The pellets 102 are carried at regular intervals by a ribbon 104 unwound from a storage roller 106. After removing the pellets, the ribbon is taken up by a receiving roller 108. The rollers 106 and 108 are rotatably mounted in bearings supported by the carriage 52.

The ribbon 104 carrying the pellets 102 is unwound from the roller 106 passing between two drive rollers 110 pressed against each other and driven by a stepping motor 112. The latter controls the intermittent advance of the ribbon 104 with steps corresponding to that of the pellets 102 on the ribbon. The rewinding of the bare tape 104 on the roller 108 is provided by a motor (not shown) connected to the roller 108 by a torque limiter.

The self-adhesive discs 102 are deposited on the film 32 by means of an applicator 114. This consists of a jack whose rod carries at its end a sole 116 over which the tape 104 passes.

The dispensing device 100 is controlled by the computer 68 so as to deposit several pellets 102 straddling each contour cut out from the film 32. A dispensing cycle includes lowering the applicator 114 to fix a tablet by pressing on the film surface 32, raising the applicator 114 and advancing one step of the ribbon 104.

The pads can be fixed at regular intervals or not along the cut contour, as and when cutting. The application of a patch 102 on the film can be carried out while the carriage 52 is stopped, or on the fly, while the carriage 52 is moving. In the latter case, it is preferable that the speed of the carriage is relatively reduced. In order not to penalize the cutting speed by stops or slowdowns imposed on the carriage 52, it is possible to choose to deposit pellets at times when, in the cutting cycle, the carriage 52 is stationary in X, Y or moves at low speed (interruption of the feed at the end of the contour or for passing an angle with abrupt change of direction, or slowing down of the feed when cutting a portion of a delicate contour, for example a notch). The positioning of the depositing device immediately behind the tool allows it to precisely follow the cut contour.

Figure 7 shows another device 120 for forming localized fasteners, this performing localized welding of the film overlapping the contour, under the effect of heat. The device 120 is mounted on the carriage 52 supporting the cutting head, immediately behind the cutting tool. It includes an applicator 122 in the form of a jack, the rod of which carries, at its end, a crowbar 124, or sole, or heating punch. Welding is carried out by lowering the applicator 122 to bring the presser foot 124 into contact with the film 32.

As in the previous embodiment, several fasteners located along each cut contour are produced, at regular or irregular intervals, each fastener preferably being formed when the advance of the cutting tool is interrupted or slowed down. In order to facilitate the welding, a product having a welding promoter function can be deposited on the film 32. The deposition is carried out over a certain width on either side of the cut contour, either continuously or at the locations provided. for the attachments to be made. To this end, the carriage 52 carries a spray nozzle 126 connected to a reservoir (not shown) by a flexible pipe provided with a solenoid valve 128 controlled by the installation computer. The spray nozzle 126 is located between the cutting tool (not shown in Figure 7) and the applicator 122, or in front of the cutting tool.

Consideration has been given above to means for forming fasteners located at different locations around the contours of the cut film parts.

Figure 8 shows a device 130 allowing the formation of continuous fasteners along the contours of the cut film parts.

The device 130 is mounted on the carriage 52 supporting the cutting head, immediately behind the cutting tool. It includes an applicator 132 in the form of a jack, the rod of which carries, at its end, a heating roller 134. The applicator 132 is supported by the carriage 52 by means of a rotary plate 135. The plate 135 is controlled in rotation about its vertical axis in synchronism with the rotary table carrying the cutting tool.

Welding is carried out by pressure exerted by the heating roller 134 on the film 32 under the action of the applicator.

In order to facilitate the welding, a product having a welding promoter function can be placed on the film 32. The deposition is carried out over a certain width on either side of the cut contour, continuously. To this end, the carriage 52 carries a spray nozzle 136 connected to a reservoir (not shown) by a flexible pipe provided with a solenoid valve 138 controlled by the installation computer. The spray nozzle is located in front of the applicator 132, in front of or behind the cutting tool.

It is thus possible to reconstitute the film 32 in a practically perfect manner. It will be noted that, in the embodiments of FIGS. 7 and 8, the welding can be carried out not by application of a heating element but by projection of laser radiation. In the embodiments of FIGS. 5 to 8, the device for removing or forming fasteners is carried by the carriage 52 for supporting the cutting head. Other embodiments can be envisaged in which this device is independent of the cutting head, which makes it possible to avoid that the cutting speed is possibly affected by the laying or formation of the fasteners.

Figures 9 and 10 show a device 140 designed to deposit strips of adhesive film over the entire width of the mattress 30 covered by the film 32, at the downstream end of the cutting table, before detachment of the film 32.

The device 140 comprises a carriage 142 movable transversely, parallel to the direction Y, along a beam 144 having a fixed position in direction X, immediately upstream of the deflector 74. The carriage 142 is guided by the beam 144 and is in taken with an endless screw 144a parallel to the beam 144 and driven by a motor 146.

At one end of the beam 144 is mounted a roll 148 of adhesive film 150. The carriage 142 carries a clamp support 152 capable of coming into engagement laterally with the adhesive film 150 and a pressure roller 154. The clamp 152 is mounted on its support by being movable horizontally in direction Y between a retracted position and a gripping position, under the control of an actuator. The clamp 152 and the roller 154 are movable vertically between a raised position and a lowered position by being fixed to the ends of the rods of two respective actuators 152a, 154a. At the outlet from the storage roller 148, the adhesive film 150 passes successively between the blades of a cutting device 156 and under an applicator 158. The latter is formed by a roller movable vertically between a raised position and a lowered position by being fixed at the end of an actuator 158a.

A cycle for removing a transverse strip of adhesive film 150 comprises the following operations. The clamp 152, the roller 154 and the applicator 158 being in the raised position, the clamp 152 unwinds the film 150, while being in engagement with the end thereof, by displacement of the carriage 142 in a direction (go) under the engine control 146. When the adhesive film 150 has been unwound over the entire width of the mattress, above it, the clamp 152, the roller 154 and the applicator 158 are lowered to bring the adhesive film 150 to the film contact 32. The clamp 152 is then opened, retracted and raised and the movement of the carriage 142 is controlled in the other direction (return) by means of the motor 146. During this return journey, the pressure roller in the lowered position applies the strip of adhesive film on the film 32. When the carriage has returned to the initial position, the clamp 152 is brought into the gripping position to grip the film 150 between the roller 148 and the cutting device 156. Next, the cutting device is actuated, and the roller 154 and the applica 158 are noted. A new cycle can then be carried out by moving the carriage 142 on its outward journey. Each strip of adhesive film is deposited between two steps in advance of the mattress. The interval between strips in the Y direction is chosen to ensure that each cut contour is covered by at least two strips. This interval can be regular, or adapted to the dimensions of the different contours in the Y direction.

Figures 11 and 12 show yet another embodiment of a device for forming localized fasteners. As in the previous embodiment, this device 160 is carried by a carriage 162 separate from that supporting the cutting head. The carriage 162 is movable transversely, parallel to the direction Y, along a beam 164 having a fixed position in direction X, immediately upstream of the deflector 74. The carriage 162 is guided by the beam 164 and is engaged with a worm 164a parallel to the beam 164 and driven by a motor 166. The carriage 162 carries a spray nozzle 168 connected to a pressurized tank (not shown) containing a welding promoting material by a flexible pipe 170 provided with a solenoid valve 174. In addition, the carriage 162 carries a mirror 176 intended to reflect towards the surface of the film 32 a laser radiation produced by a generator 178 located on one side of the installation.

The welding promoter material can be projected when the carriage 162 is moved in one direction in the Y direction, while the welding is carried out by heating by means of laser radiation by actuating the generator when the carriage 162 is moved in the other direction. . Welding can be limited to the areas of intersection between the contours and the X-ray path of the laser radiation, by corresponding modulation of the radiation produced by the generator.

The intervals between welding lines are chosen, in the same way as the intervals between strips of adhesive film in the previous example, so that each contour is cut by at least two welding lines.

It will be noted that the heating for welding can be carried out not by projection of laser radiation, but by application of a heating element, for example a heating roller carried by the carriage 162. There have been described above devices for removing or forming fasteners useful for recovering a reconstituted film 32.

In the case where only the skeleton of the film 32 is recovered, but must be provided with fasteners in cut parts, in order to maintain its integrity, such a device for removing or forming localized fasteners can be used. The device as described with reference to FIGS. 6 and 7 or to FIG. 8 is more particularly suitable because, by positioning the carriage 52 in X and Y, it makes it possible to deposit an adhesive patch or to form an attachment by welding at a precise location. of the film 32. A second embodiment of the invention is shown in FIGS. 13 to 17. This embodiment differs from that of FIGS. 1 to 4 only by the means for recovering the fragments of sealing film in the downstream end zone of the cutting table. The other elements of the installation are common to the two embodiments. These common elements have the same reference numbers and will not be described again in detail.

The fragments of the sealing film 32, that is to say the skeleton 32 'and the parts of film 32 "cut with the parts in the mattress 30, are removed by suction at the downstream end of the cutting table 20 at means of a movable member 200 to be released out of the path of the mattress and brought to a discharge device 250.

The movable member 200, shown in more detail in FIGS. 15 to 17, is in the form of a sectorized annular hollow drum. It comprises a hub 202, an outer wall 204 traversed by a plurality of openings 206 and radial partitions 208 which extend all along the drum between the hub and the outer wall. The partitions 208 divide the drum into several sectors 210. These are six in number in the example illustrated, but this number may be different.

The openings 206 make each sector communicate with the outside, at the peripheral surface 205 of the drum, over the entire length of the latter. The openings 206 may be in the form of perforations or slots, for example circumferential slots extending over part of the circumference of the drum, in correspondence with each sector, as in the example illustrated. At its axial ends, the sectors of the drum 200 are closed by annular flanges 212, 214 fixed to the drum. The drum 200 is mounted on an axis 216, the ends of which are engaged through plate openings 218, 220 forming bearings. The drum 200 is free to rotate about the axis 216.

The evacuation device 250 comprises a receiving tank or receptacle 252 fixed to the plates 218, 220, immediately downstream of the drum 200. The tank 252 has a horizontal bottom wall 254, located substantially at the same level as that of the bottom edges of the plates 218, 220. The wall 254 is folded back at its upstream end to form a rim 256 situated behind the downstream generator 200b of the drum. At its downstream end, the wall 254 is folded back to form a downstream wall 258 of the tank 252.

At its ends, the container 252 is provided with side walls 260, 262. These are fixed on a tab 264 secured to the plates 218, 220 and support all of the longitudinal walls 254, 256, 258 of the container. As shown only in FIG. 14, the evacuation device 250 can also comprise an extraction system by worm screw 270. This is fixed, with its drive motor 272, on one of the side walls 260 of the tank reception 252. The fragments of sealing film recovered in the tank are extracted by the screw 270 through an opening formed in the other side wall 262 and communicating, for example, with a chute 274.

The plates 218, 220 supporting the drum 200 and the discharge device 250 are pivotally mounted about a horizontal axis on supports 222, 224. These latter are fixed to the chassis of the cutting table 20, on each side of this one. Pivots 226, 228 carried by the supports 222, 224 pass through openings in the plates 218, 220 located in the lower parts thereof. In this way, the assembly comprising the drum 200 and the receiving tank 252, articulated on the supports 222, 224 rests by its weight on the mattress 30 coated with the film 32. As shown in FIG. 15, the lower generator 200a of the drum is located at a level lower than that of the lower edges of the plates 218, 220, so that the contact between the drum 200 and the mattress 30 occurs only along the generator 200a.

The rotation drive of the drum 200 with the flanges 212, 214 around the axis 216 is therefore carried out by contact with the mattress 30 when the latter is advanced under the control of the motor 28 driving the conveyor 22. As a variant, the drum 200 can be driven in rotation by a drive device, preferably disengageable, associated with an independent motorization or driven by means of the motor 28, in synchronism with the conveyor 22. A contact between the drum 200 and the mattress 30 is then not necessary, the surface of the drum can simply be flush with that of the mattress.

One of the flanges 212, 214, for example the flange 212 is provided with openings 234, for example circular, (Figures 15 and 16) which are in number equal to that of the sectors 210 and each located in the extension of a sector. The plate 218 which is in contact, practically without play, with the flange 212 has two openings or openings 236, 238. Lines 240, 242 connect the openings 236, 238 (Figure 15) respectively to a vacuum source and to a source pressurized air (not shown). The apertures 236 and 238 each extend along an arc with a central line located substantially on the same circumference as the centers of the apertures 234 and a width substantially equal to the dimension of the apertures 234. The aperture 236 extends from a point 236a located slightly downstream of the generator 200a of the drum to a point 236b located substantially at the level of the generator 200b of the drum. The light 238 extends from a point 238a located substantially at equal angular distance from the generator 200b and the upper generator 200c of the drum to a point 238b located substantially at the level of this generator 200ç. In this way, when the outer surface part of the drum corresponding to a sector (for example the sector 210a in FIG. 15) comes into contact with the mattress 30 provided with the film 32, communication is established between the vacuum source and this sector through the upstream part of the light 236 and the opening 234a corresponding to the sector 210a (hatched area in FIG. 15). The outer surface of the drum is therefore placed under vacuum when it comes into contact with the film 32. This placing under vacuum is continued until the opening 234a ceases to be in correspondence with the downstream end 234a ceases to be in correspondence with the downstream end 236b of the lumen 236. The fragments of the sealing film which have been sucked in and deviated from the trajectory of the mattress 30 are then released. When a sector (for example sector 21 Od in Figure 15) arrives in a position angular in which a communication is established between the opening 234d associated with this sector and the light 238 (hatched area in FIG. 15), an overpressure is established through the surface of the drum 200 to take off any fragments of film which may remain on the drum, despite the prior cut off of the suction.

The angular position of the lights 236, 238 makes it possible to carry out a suction between the moment when the drum arrives near the mattress covered with the film and the moment when the drum overhangs the interior of the receiving tank 252 (the upstream wall 256 of the latter. ci being upstream of the downstream generator 200b of the drum), and of producing a backflow after the suction until about the moment when the surface of the drum passes at the level of the upper generator 200c. Thus, it is ensured that the fragments of film sucked are well evacuated in the tank 252. The angular distance between the points 236b and 238a of the lights

236 and 238 is at least equal to the angular dimension of an opening 234, so that the same opening is not simultaneously opposite the openings 236, 238. The maximum angular interval between the start of the delivery and the end of the delivery, or between the beginning of the aspiration and the end of the aspiration, determine the maximum angle of each sector and therefore the minimum number of these. In practice, this minimum number is equal to 4, preferably to 5. It will also be noted that fragments of sealing film may be of small dimensions, in certain cutting configurations, the density of the openings 206 on the surface of the drum must to be quite high. In the case of circumferential slots, as in the example illustrated, the pitch between slots is chosen between approximately 5 mm and 20 mm.

It will also be noted that the overpressure discharge of the film fragments taken by the rotary drum may not be necessary.

Figures 18 to 20 illustrate an alternative embodiment of the installation of Figures 13 to 17, the difference being in the embodiment of the discharge device.

In the installation of FIGS. 18 to 20, the evacuation of the fragments of sealing film is carried out by transfer through an evacuation pipe 290 between a reception tank 280 and a device for recovery 292, the film fragments being for example collected in a carriage 294.

The receiving tank 280 has the shape of a hood which opens at its lower part in the immediate vicinity of the surface of the drum 200. The opening 282 of the hood 280 extends substantially from immediately before the end of the zone of suction until the end of the discharge zone (shown diagrammatically in Figure 20).

The fragments of sealing film collected in the hood 280 are propelled by the pressurized air used for the discharge, to reach the recovery device 292, through the line 290.

Claims

1. Method for automatic cutting of sheet material of the type comprising supplying at least one ply of sheet material to a cutting table, maintaining the sheet material on the table by vacuum, applying a sealing film on the surface of the sheet material, the cutting of pieces of predetermined shapes by means of a tool passing through the sealing film and the sheet material, and the evacuation of cut pieces downstream of the cutting table. characterized in that at least the skeleton of the sealing film is deflected from the path of the sheet material in a downstream end zone of the table to be recovered automatically, separately from the cut pieces.

2. Method according to claim 1, characterized in that at least the skeleton of the sealing film is recovered by automatic rewinding.

3. Method according to claim 2, characterized in that the rewinding is carried out by call on a mandrel at a tangential speed controlled by the speed of movement of the sheet material on the cutting table.

4. Method according to any one of claims 1 to 3, characterized in that the cutting of the parts is carried out while preserving the integrity of the skeleton of the sealing film.

5. Method according to any one of claims 1 to 4, characterized in that it comprises the removal or formation of fasteners connecting to the skeleton of the sealing film at least some parts of the sealing film cut with the parts.

6. Method according to claim 5, characterized in that it comprises the removal or formation of fasteners connecting to the skeleton of the sealing film each of the parts of the sealing film cut with the parts from the sheet material, so recovering a substantially reconstituted waterproof film.

7. Method according to any one of claims 5 and 6, characterized in that one attaches fasteners in the form of self-adhesive elements along the contours of the parts of the sealing film cut with the parts.

8. Method according to any one of claims 5 and 6, characterized in that fasteners are formed by welding the sealing film along the contours of the parts of the sealing film cut with the parts.

9. Method according to claim 8, characterized in that, prior to welding, a welding promoting material is deposited on the sealing film.

10. Method according to any one of claims 8 and 9, characterized in that the welding is carried out by application of a heating element.

11. Method according to any one of claims 8 and 9, characterized in that the welding is carried out by projection of laser radiation.

12. Method according to any one of claims 5 to 11, characterized in that the fasteners are produced in a localized manner at different locations along the contours of the parts of the sealing film cut with the parts.

13. Method according to any one of claims 5 to 11, characterized in that the fasteners are made continuously along the contours of the parts of the sealing film cut with the parts.

14. Method according to any one of claims 5 to 13, characterized in that the removal or formation of fasteners is carried out immediately after cutting, following the path of the cutting tool.

15. Method according to any one of claims 5 and 6, characterized in that localized fasteners are formed by fixing strips of adhesive film on the sealing film, in a transverse direction relative to the path of the material in sheet, after cutting the parts and before deflection of the sealing film with respect to the path of the sheet material.

16. Method according to any one of claims 8 to 11, characterized in that localized fasteners are formed in the form of welding lines in transverse direction with respect to the path of the sheet material, after cutting of the parts and before deviation of the sealing film from the path of the sheet material.

17. Method according to claim 1, characterized in that fragments of the sealing film constituted by the skeleton and parts of the film cut with the pieces are removed by suction from the path of the sheet material and then removed.

18. The method of claim 17, characterized in that the removal of the wire fragments is carried out by means of a movable member adjacent to the path of the sheet material.

19. The method of claim 18, characterized in that the movable member is rotated by contact with the sheet material and advance thereof.

20. Method according to any one of claims 18 and 19, characterized in that a rotary movable member comprising several sectors is used and a vacuum is established in each sector during the movement of the latter between a location located at the proximity to the path of the sheet material and an area for removing film fragments.

21. The method of claim 20, characterized in that an overpressure is established in each sector when it reaches the evacuation zone.

22. Method according to any one of claims 17 to 21, characterized in that the film fragments are discharged by deposition in a receptacle situated above the path of the sheet material and extraction from the receptacle.

23. Method according to any one of claims 17 to 22, characterized in that the film fragments are evacuated by being brought to an evacuation duct.

24. Method according to any one of claims 1 to 16, characterized in that the sealing film is spread over the sheet material.

25. Installation for automatic cutting of sheet material, comprising a cutting table (20), a station (12) for loading sheet material to be cut at an upstream end of the cutting table, an unloading station (16) of pieces cut at a downstream end of the cutting table, means (24, 26) of establishing a vacuum on the surface of the cutting table, and means (34, 42) for feeding a flexible sealing film (32) in the vicinity of the upstream end of the cutting table, characterized in that it further comprises means (74, 70) for separating at least one skeleton (32 ') of film d sealing (32) at near the downstream end of the cutting table (20) and to automatically recover it from the station (16) for unloading cut pieces.

26. Installation according to claim 25, characterized in that it comprises means (70) for winding at least the skeleton (32 ') of the sealing film (32).

27. Installation according to claim 26, comprising means (28) for advancing the sheet material on the cutting table (20), characterized in that the winding means (70) are connected to the advancement means (28) by a mechanical link (80) intended to control the tangential winding speed to the speed of advance on the cutting table.

28. Installation according to claim 26, comprising means (28) for advancing the sheet material on the cutting table (20), characterized in that the winding means (70) comprise a particular motor whose control is slaved to the speed of advance on the cutting table.

29. Installation according to any one of claims 18 to 28, characterized in that it comprises a device (100; 120; 140; 160) for depositing or forming fasteners on the surface of the sealing film, on the cutting table (20).

30. Installation according to claim 29, characterized in that the device (120; 130; 160) for forming fasteners comprises means for welding the sealing film.

31. Installation according to claim 30, characterized in that the welding means comprise a heating element (124; 134) and means (122; 132) for applying the heating element to the surface of the sealing film.

32. Installation according to claim 31, comprising a cutting head (50) mounted on a carriage (52) movable above the cutting table (20), characterized in that the heating element is mounted on said carriage ( 52).

33. Installation according to claim 29, characterized in that the welding means comprise means for projecting laser radiation onto the surface of the sealing film.

34. Installation according to any one of claims 30 to 33, characterized in that it comprises means for projecting a welding promoter material onto the surface of the sealing film.

35. Installation according to claim 29, characterized in that the device (100; 140) for fitting fasteners comprises means for applying adhesive elements to the sealing film.

36. Installation according to claim 35, characterized in that the device (100) for fitting fasteners comprises means for applying self-adhesive pads (102).

37. Installation according to claim 36, comprising a cutting head (50) mounted on a carriage (52) movable above the cutting table (20), characterized in that the means for applying self-adhesive pads are carried by said carriage.

38. Installation according to claim 35, characterized in that the device (100) for fitting fasteners comprises means for applying strips of adhesive film in a transverse direction relative to the advance of the flexible sheet material.

39. Installation according to claim 25, characterized in that it comprises means (200) of sampling by suction of fragments of sealing film, in the vicinity of the downstream end of the cutting table, and means (250 ; 280) removal of fragments of film removed.

40. Installation according to claim 39, characterized in that the suction withdrawal means comprise a rotary drum (200) having several sectors (210) which communicate with the outside through orifices opening on the surface of the drum, and means (236, 240) for depressurizing the sectors on a part of their rotational path between a location located near the plane of the cutting table (20) and a location located near the means (250; 280 ) evacuation of film fragments.

41. Installation according to claim 40, characterized in that the drum (200) is adjacent to at least one of its axial ends to a fixed plate (218) provided with at least one orifice (236) for connection to a vacuum source.

42. Installation according to any one of claims 40 and 41, characterized in that it further comprises means (238, 242) for boosting the sectors over part of their path in rotation, at least at the level of the means of evacuation (250; 280).

43. Installation according to claim 42, characterized in that the drum (200) is adjacent to at least one of its axial ends to a fixed plate (218) provided with at least one orifice (238) for connection to a pressurized air source.

44. Installation according to any one of claims 40 to 43, characterized in that the drum (200) is mounted to rotate freely, so that the drum is driven in rotation by contact with its surface.

45. Installation according to any one of claims 39 to 44, characterized in that the means for removing film fragments comprise a tank (252) located above the plane of the cutting table (20) and means ( 270) for extracting film fragments from the receptacle.

46. Installation according to any one of claims 39 to 44, characterized in that the means for removing film fragments comprise a pipe (280, 290) which is connected to an opening (282) situated above the plane of the cutting table (20) to collect the fragments of sucked film.

47. Installation according to any one of claims 25 to 46, characterized in that it comprises means (40) for spreading the waterproof film (32) on the sheet material (30).