FR2924367A1 - Material strip advancing device for machine tool i.e. press, has maneuvering plate connected to machine tool by integration arm such that movement of machine tool directly induces displacement of maneuvering plate - Google Patents

Abstract

The device (7) has fixed and movable locking units i.e. clamps (15f, 15m), locking a strip of material (5). The clamp (15m) is displaced between open and closed positions and between an advanced position and a withdrawn position in which the clamp (15m) is withdrawn with respect to a machine tool (3) i.e. press. A movable maneuvering unit i.e. maneuvering plate (11), maneuvers the clamps during its displacement. The plate is connected to the tool by an integration arm (12) such that movement of the tool directly induces displacement of the plate.

Description

The invention relates to a device for feeding a strip material intended to feed a machine tool. BACKGROUND OF THE INVENTION The invention also relates to a machine equipped with such a device.

A machine tool, in particular of the press type, makes it possible, starting from web material, for example metal sheets, to perform cutting, pressing, gluing or welding operations using a tool. The strip of material runs on a working table of the machine where, regularly, the tool performs an operation from at least one side, upper and / or lower, of the strip. This tool is movable in translation in a direction not parallel to a longitudinal axis of the strip. It is sometimes necessary to bring on the work table of the machine several strips of material, coming from various directions, for example for producing a multi-material product.

In all cases, the advance of the band or bands must be fast, regular and precise. Indeed, given the work rates generally observed on this type of machine, the advance of the band must be controlled, so as to achieve significant amounts of identical parts, consistent with specifications.

For this, the machine tool is generally equipped with a tape feed device, integrated into the machine. Consequently, it is not easy to modify this device to adapt it to another type of production, with another tool. Moreover, the position of this feed device relative to the machine tool is generally predetermined. This device is relatively bulky, it does not facilitate the insertion of the machine on an existing production line. FR-A-2 383 866 discloses a tape feed device which comprises a belt support carriage. This carriage is movable in translation according to a predetermined reciprocating movement. The carriage is equipped with a first fixed clamping pliers and a second movable clamping clamp of the strip. These clamps are alternately opened and closed by means of hydraulic cylinders. The clamps are synchronized with the movements of the carriage. The belt in position on the carriage is held by the movable clamp, then the carriage is moved towards the machine tool. The fixed clamp then holds the band in position under the tool, the movable clamp opens and the carriage returns to its initial position. EP-A-1 640 084 also discloses a belt feed device in which a plurality of clamping members are attached to an endless toothed belt. The drive in rotation of the belt, and therefore the clamping members, is performed by an electric motor. For the implementation of the clamping members, hydraulic cylinders are provided. Such devices use means of advance and / or clamping which require, for the return to the initial position, a relatively large time, which hampers the use of such systems for the production of parts at high rates. Moreover, the operation of such advance devices does not allow to achieve a greed band perfectly synchronized with the movements of the tool, which can cause defects on some of the parts made. Also known from FR-A-2 809 660 a coin transfer device comprising an arm with housing receiving parts. This arm performs, under the action of a slide, an up or down movement, simultaneously with a forward movement or recoil. The tool is integral with the slide. Such a device is adapted to a synchronous transfer of single parts but it does not allow to ensure the advance and the holding in position of a band. In addition, it is not suitable for production at high rates. It is these drawbacks that the invention intends to remedy more particularly by proposing a device for feeding a strip material, easy to install on machine tools and allowing the production of parts at high speeds, with positioning Precise band under the tool.

For this purpose, the subject of the invention is a device for avarice of a web material intended to feed a machine tool, equipped at least with a tool that is mobile in a non-parallel direction, in particular perpendicular to a direction of advance of the strip, this device comprising at least two clamping members of the strip of material, one of the members, said fixed, being adapted to move between an open position and a closed position and one of the bodies, said mobile, being adapted for moving, on the one hand, between an open position and a closed position and, on the other hand, between an advanced position and a position removed relative to the tool, characterized in that it further comprises at least one movable operating member adapted to maneuver during its displacement the fixed and movable clamping members and in that this actuating member is connected by a securing means to the tool, so that a movement of the tool induces directem ent a displacement of the actuator.

An operating member of the fixed and movable clamping members, connected to the tool, therefore moves concomitantly and synchronously with the latter. This makes it possible to have synchronized movements of opening, closing and advance of the clamping members. This feed device is adaptable to different machine tools as well as to the number and / or positions of the material strip or strips with respect to the machine. According to advantageous but non-obligatory aspects of the invention, the feed device may incorporate one or more of the following features: The operating member comprises at least one plate provided with at least one guide path of the feed members. Tightening. - The guideways have two types of slots in the plate. A first type of slot comprises two non-rectilinear slots, configured in S and arranged in a mirror of one another. - A second type of slot comprises three non-rectilinear slots, configured in S, the distance between the same edge of the lower end and the upper end of some of the slots corresponding to a step in advance of the band. - The fixed clamping member is a fixed clamp formed of a so-called fixed jaw secured to the frame and a so-called movable jaw, movable vertically above the fixed jaw. - The upper jaw of the fixed clamping member is operated by sliders provided with fingers inserted into the slots of the plate. - The movable clamping member is a movable clamp formed of a lower jaw with a T-shaped cross-section, movable in a direction parallel to a direction of travel of the band and an upper jaw moving vertically above the lower jaw. - The upper jaw of the mobile clamping member esi: maneuvered by sliders provided with fingers inserted into the slots of the plate. - The upper jaws of the fixed and movable clamps are connected by bars to sliders movable in translation parallel to a direction of advance of the strip, said sliders being adapted to manipulate said jaws during their movement. - The slides are equipped with operating fingers inserted in the slots of the plate so as to be displaced when the plate moves. - The lower jaw of the mobile clamp is equipped with fingers inserted into the middle slot of the second type of slots. The invention also relates to a machine tool equipped with a device for feeding a strip material according to one of the preceding characteristics. The invention will be better understood and other advantages thereof will appear more clearly on reading the following description of an embodiment of an advance device according to the invention, given solely for of example and made with reference to the accompanying drawings in which: - Figure 1 is a perspective view of an advance device according to the invention, a tool and a machine tool being schematically represented on another scale for Figure 2 is a top view of the device of Figure 1, without the machine tool, - Figures 3 to 10 are side views, according to the arrow III in Figure 1 of the device in different positions. during an operating cycle of the device and - Figure 11 is a side view, on another scale, of the operating member. A schematic representation of a type of machine tool on which the device can be mounted is given in FIG. 1. This machine tool, of the press type, comprises a working table 1. In the upper part, a bracket 2, schematically illustrated , supports a tool 3. The latter is held in position above the work table. In a vertical reciprocating movement, according to the double arrow F1, the tool 3 can move away from and move closer to the work table 1 in order to perform a predetermined operation on a portion 4 of a strip 5 of material positioned on the This band 5 generally has a width of between 3 millimeters and 100 millimeters and a thickness of between 0.1 millimeters and 5 millimeters. Such strips are generally formed from metallic materials and commonly referred to as strip. These bands have long lengths, generally between 5 meters and 5000 meters. This band 5 moves towards the tool 3 in a direction F2 substantially parallel to a main face 6 of the work table 1.

The tool 3, it, moves above the band 5, in a direction FI substantially perpendicular to the main face 6 of the work table 1. Control members and drive members, for example electric, hydraulic or pneumatic , known per se and not shown, allow the implementation of the tool.

In the example, the tool 3 and a device 7 for advancing the band 5, according to the invention, are arranged one behind the other. Alternatively, the arrangement is different and adapted to the configuration of the production line.

Such a tool makes it possible to perform operations of folding, stamping, cutting, gluing or welding on a strip 5 of material. These operations are generally performed between 30 cycles and 400 tool operating cycles per minute. For example, for the production of two-component parts, it is possible to produce about 400 pieces per minute. Given these rates, it is important to obtain a regular and accurate advance of the band 5 under the tool 3 to avoid any variation in the position of the part 4 of the band on the work table 1. L Advance of the band must be perfectly synchronized with the movements of the tool. The feed device 7 comprises a generally parallelogram-shaped frame 8 formed of two parts, upper 9 and lower 10. The frame 8 is fixed, for example removably, either to the floor of the workshop or to a fixed part of the machine tool, for example to the work table 1. Such a device can be mounted so as to be easily separable from the machine tool. Alternatively, the frame is permanently attached to the machine tool. A passage is provided between the two parts, upper 9 and lower 10, of the frame 8 to allow the band 5 to move.

At least one device 11 of the device, configured as a flat plate 11, is arranged outside the frame 8. In the example, a single actuating member 11 is shown for greater readability. Advantageously, the device 7 can be equipped with two identical parallel actuating members 11 located on either side of the frame 8. The plate 11 is oriented perpendicular to the main face 6 of the work table 1, in one direction parallel to the direction F1 of movement of the tool 3. The tool 3 is connected to the actuator 11 by a securing means 12, advantageously removably connected to the tool 3. It is, for example, example, an arm 12 fixed by a screw system, to the part of the bracket 2 carrying the tool 3. Alternatively, the securing means 12 may be permanently connected to the tool 3.

The frame 8, in which the strip 5 passes, is located near the tool 3. The device 7 can be moved from one machine to another or from one side to the other of the same machine in function needs. It is also possible to provide several devices 7 around a machine, each device ensuring the advance of a strip 5 of given material. The actuating plate 11 is not fixed to the frame 8 of the device 7. It is connected only to the tool 3 by the securing arm 12. In other words, any displacement of the plate 11 is directly induced by a movement of the tool 3.

The plate 11 is equipped with at least one guide path 13, 13 'of the clamping members. In this case, these guide paths are formed by two types of slots 13, 13 'or elongated orifices, through, of particular geometry, formed in the plate. These slots 13, 13 'allow guiding guide means 14f, 14m clamping members 15f, 15m. Thus, the guiding means 14f, 14m move concomitantly with the movement of the tool, which allows to fasten directly, without intermediate, the feed means 15f, 15m of the band 5 to the movements of the tool 3. In this way, there is optimal synchronization of the advance of the band 5 with the movement of the tool 3.

The clamping members or clamps 15f, 15m perform the advance of the band 5, by the pinching and releasing, alternately, thereof in order to bring it regularly in position on the work table 1, below of the tool 3. In variants not shown, there are several clamping members in one or more advance devices. The presence of several advance devices, for example upstream and downstream of the working zone of the tool 3 makes it possible to ensure rectilinear and synchronous avarice of the thin strips by avoiding an accordion folding effect of the bandaged. In this case, the device 7 shown comprises two clamps 15f, 15m.

A clamp 15f, said fixed, ensures the blocking position of the band 5 when the portion 4 of the band is under the tool 3. This clamp 15f ensures the holding in position of the band 5 during the work of the tool 3 in order to avoid any displacement of the band 5 under the action of the tool 3. For this, the clamp 15f is adapted to move from an open position to a closed position around the band 5. Another clamp 15m, said mobile, allows to take, by pinching, the band at a first position, said withdrawn, predefined and located upstream of the working area of the tool 3 and to bring the band 5 to a second position, said advanced, also predefined, where the band 5 is in the tool's working area. In other words, the movable clamp 15m is adapted to occupy four extreme positions, namely two positions, opening or closing, in the advanced position and two positions, opening or closing, in the withdrawn position. These positions are combinable with each other in a pre-established sequence and the clamp 15m can occupy any intermediate position between these four extreme positions. The so-called fixed clamp 15f is formed of two jaws 16, 17. A so-called fixed jaw 16 is positioned facing one of the faces, in the example the lower face 18, of the band 5. In a variant, it can be positioned next to the upper face of the band. This jaw 16 is secured to the lower portion 10 of the frame 8. Advantageously, it is integral with the latter. Alternatively, it can be reported by gluing, welding or screwing. In the example, the fixed jaw 16 extends perpendicularly to the running direction F2 of the strip 5, that is to say along the width of the strip 5, advantageously over the entire width of the frame 8. In Other embodiments not shown, this fixed jaw extends only over a portion of the width of the strip. This fixed jaw 16 provides a sufficient contact surface with the band to ensure the grip of the band 5. For this, it is configured in parallelogram of which one face is in contact with the material strip. This fixed jaw is surmounted by a so-called mobile jaw 17, of complementary shape, so as to ensure a nip of the band 5 between the facing faces of the fixed jaws 16 and mobile 17. The movable jaw, in the example, is in the form of a bar with a square section, each end of which is provided, in the central position, with a finger 19 of a length such that these fingers 19 are inserted into the ends of two flattened strips 21 or connecting rods arranged in a V-shape. The opposite ends of the bars 20 are traversed by fingers 22. These fingers 22 are located at the ends of sliders 23, in the central position. The fingers 22 are parallel to the fingers 19 and they extend beyond the frame 8. They are longer than the fingers 19. In all cases the length of the fingers 22 is sufficient for them are inserted into the slots 13. The sliders 23 form actuating members. These actuating members 23 are slidably mounted on two parallel shafts 24 passing through them, in the vicinity of their ends. Alternatively, the members 23 are mounted on a different number of trees, for example, one or more than two. The members 23, in a non-illustrated embodiment, are mounted on rails or slideways equipped with ball bearings. The shafts 24 are located in the upper part 9 of the frame 8, above the band 5 and they are oriented parallel to the running direction F2 of the band. Thus the sliders 23 are movable in translation in the direction of travel of the strip. The connecting bars 20 connect the fingers 22 of the sliders 23 and the fingers 19 of the movable jaw 17. The links of the bars 20 with the movable jaw 17 and the sliders 23 are free to rotate. In other words, an articulated rod system is produced with two sliders 23 and a jaw 17 arranged in a triangle and articulated together by two bars 20. The fingers 22 of the sliders 23 are inserted into guideways 13 it is that is to say in the slots 13 formed in the side plate 11. These slots 13 are non-rectilinear and generally configured in S. They are arranged in a mirror of one another, so as to thus have a variable variation between their nearest edges. These slots 13 are located on either side of the movable jaw 17 when the plate 11 is in place against the frame 8. Each slot 13 is oriented in a direction substantially perpendicular to the running direction F2 of the strip. The movable jaw 17 reciprocates up and down above the fixed jaw 16. This movement of approaching and moving the jaws 16, 17 is guided by vertical shafts 25 passing through the jaws 16, 17 to the jaws 16, 17. near their ends. The shafts 25 are perpendicular to the shafts 24. One end of each shaft 25 is traversed by a shaft 24. Thus, the movement of the clamp 15f is guided, the jaws 16, 17 always being aligned one above the other whether the clamp is open or closed. The jaw 17 thus performs a vertical reciprocating movement, so as to be in the lower position resting on the upper face of the band 5 and blocking it against the fixed jaw 16. When the movable jaw 17 is in the up position, it is no longer in contact with the upper face of the strip of material. The latter is not locked in position between the two jaws 16, 17 and the band 5 is free relative to the fixed clamp 15f.

It is also appropriate to associate the movements of the fixed clamp 15f with the movements of the movable clamp 15m. In particular, the movements of these two clamping members must be coordinated and in direct dependence of the movements of the tool. For this, the movable clamp 15m comprises a carriage 26 slidably mounted inside the lower portion 10 of the frame 8. This carriage 26, whose cross section is configured inverted T, advantageously extends over the entire width of the frame 8, and at least on the width of the band. It is slidably mounted on two parallel shafts 27, identical to the shafts 24 of the sliders 23 of the fixed clamp 15f. These two shafts 27 are located in the lower part 10 of the frame 8 and parallel to the two shafts 24. Advantageously, these four shafts 24, 27 are fixed to the front end walls 28 and rear 29 of the frame 8, in the direction of movement F2. Of the band. Thus the shafts 27 of the mobile carriage 26 also pass through the fixed jaw 16. The leg portion of the T of the carriage 26 forms a fixed jaw 30 of the movable clamp 15m. This jaw 30 forms a bearing surface for the lower face 18 of the strip 5. In the upper part, above the material strip and in front of the jaw 30, is a movable jaw 31 of complementary shape.

These two jaws 30, 31 have a length at least equal to the width of the band. In this case, they occupy the entire width of the frame 8. To position the movable jaw 31 permanently above the carriage 26, it is provided with two vertical shafts 32 oriented perpendicular to the running direction F2 of the strip . These shafts 32 are parallel to the shafts 25 and form guiding axes of the movable clamp 15m during the opening and closing movements. The upper jaw 31 is connected by two flattened connecting bars 33 or rods articulated at their ends to slides 34.

The bars 33 are arranged in V and their ends connect central fingers 35 located at the ends of the slides 34 with fingers 36 located at the ends of the jaw 31. The fingers 35, 36 are parallel to the fingers 22, 19. The slides 34 are also slidably mounted on the two shafts 27 passing through the movable carriage 26 and the fixed jaw 16. The slides 34 are located on either side of the fixed jaw 30, in the corners delimited by the jaw 30 and the crossbar of the carriage 26 configured in inverted T. In this way, the movement of the slides is guided and synchronous. In other words, these slides 34 and this movable upper jaw 31 are similar, or identical to the movable upper jaw 17 and the sliders 23 of the fixed clamp 15f. Unlike the fixed clamp 15f, the lower jaw 30 of the movable clamp 15m is provided at its ends with central fingers 37 extending outwardly. The upper jaw 31 is equipped with a central finger 36. The fingers 35, 37 are parallel to each other, of the same length, and perpendicular to the direction F2 in advance of the band. They are longer than the fingers 36 and they are inserted into the guideways 13 '. These paths are formed by three elongated slots. Each slot is made in the plate 11 and is generally configured in S. The plate 11 is thus equipped with three slots 13 'arranged side by side. Their inclined central zones are oriented in the same direction. The gap between each slot 13 'is constant over the entire length of the main part of each slot and variable at the ends of the slots. The main part of a slot includes the inclined central area and a straight portion connecting this central area at each end of the slot. The middle slot 38 receives the finger 37 of the lower jaw 30 of the movable clamping member 15m. The fingers 35 of the slides 34 are inserted in slots 39 disposed on either side of the central slot 38. These slots 38, 39 are formed in the plate 11 so that their upper ends 38s, 39s are situated approximately at the mid-length of the slots 13 receiving the fingers 22 of the movable jaw 17 of the fixed clamp 15f. In other words, the guideways of the operating members of the fixed clamping members 15f and mobile 15m are arranged offset. The slots 13 corresponding to the fixed gripper 15f are situated in the upper part of the plate 11 and those 38, 39 corresponding to the movable gripper 15m are located in the lower part of the plate 11. For the movable gripper 15m, the upper jaw 31 is positioned above the band 5 and the slides 34 for operating this jaw are located below the band 5. To achieve a vertical displacement of the upper jaw 31, that is to say to open or close the movable clamp 15m, one moves horizontally in the direction F2 in the opposite direction, the slides 34 along the shafts 27. This displacement is carried out in a plane, materialized by the shafts 27, containing the slides 34 and the jaw 30. During this displacement , the bars 33 deviate, so the V they form opens.

This causes a vertical and guided movement, along F1, of the upper jaw 31 directly proportional to the stroke of the slides 34. The vertical movement of the jaw 31 relative to the jaw 30 is guided by the vertical shafts 32. slides 34 of the movable clamp 15m, ensure a displacement, that is to say a rise or fall of the upper jaw 31 during their displacement in the slots 38, 39 according to the vertical movement of the plate 11.

In the rest of the description, the expression displacement of the fingers in the direction of means approximation of the fingers in the direction of being understood that the fingers are immobile in the vertical plane, only the plate 11, and therefore the slots 13, 38, 39 being vertically mobile.

In addition to an opening and closing movement similar to that previously described for the fixed clamp 15f, translational movement is also obtained along the shafts 24, 27 of the mobile clamp 15m. This movement is authorized by the sliding assembly of the lower jaw 30, that is to say the carriage 26, on the shafts 27 and by the vertical guidance of the jaws 30, 31. The movement of the upper jaw 31 takes place, not only vertically but also horizontally, while that of the lower jaw 30 can take place only horizontally. Thus a translation of the movable clamp 15m between a withdrawn position and an advanced position, in addition to the clamping movement.

This horizontal displacement is achieved when the mobilel5m gripper is in the closed position, in the direction of movement F2 of the band which allows to position the part 4 under the tool 3. When the movable gripper is open, the displacement then takes place in the opposite direction, which makes it possible to bring the mobile clamp 15m back to its so-called withdrawn starting position.

Damping members 40, for example spring-mounted steel parts, form stops to the sliders 23 of the upper jaw 17 of the stationary clamp 15f. These stops, grooved, are mounted above each end of each slide. They allow blocking in different positions of the slides. In other words, they involve a controlled displacement, in successive steps, the sliders 23, while ensuring a support on the sliders by the restoring force exerted by the spring, thus keeping the sliders during their movement. Identical stops 40 'are also provided for the slides 34 of the upper jaw 31 of the mobile clamp 15m, at their contact zone with the carriage 26 of the movable clamp 15m. We now describe an operating cycle of the device where the advance of the band 5 is performed during the rise of the tool 3, with reference to Figures 3 to 10, which corresponds to an advance of the band when the tool 3 moves away from the part 4 of the band, after making a part. In a non-illustrated embodiment, the advance of the band 5 is performed when the tool 3 goes down, that is to say before the production of the piece. For this, the curvature, that is to say the central zone, slots 38, 39 receiving the fingers 22, 35, 37 of the movable clamp 15m are oriented in the other direction than that shown. In a first position, illustrated in Figure 3, the movable jaw 17, shown on the right of the figure, bears on the strip 5, that is to say that the fixed clamp 15f is in the clamping position of the band 5 which is materialized by a horizontal solid line. The plate 11 is in the high position. In this case, the fingers 22 of the sliders 23 are wedged in the lower end portion 13b of the slots 13. In this part, the slots 13 have their edges facing each other in a position close to each other, the distance between the slots 13 being minimal, and the width of the slots 13. The bars 20 thus form a relatively closed angle V. The slides 23 are also in a position close to each other and this movement induces a thrust on the movable jaw 17 along the arrow F1. This movement has the effect of keeping the movable jaw 17 in abutment against the band 5.

This defines a first closing position of the fixed clamp 15f where the band 5 is immobilized. The mobile clamp 15m is, in turn, in the open position. The fingers 35 of the slides 34 of the upper jaw 31 are in position in the lower end portion 39b of the slots 39. In this part, the width of the slots 39 is minimal. The slides 34 are close to each other, bearing against the jaw 30. The V formed by the bars 33 is also a relatively closed angle. The upper jaw 31 is pushed upwards, by sliding along the shafts 32. The movable clamp 15m is in the so-called open position.

This position corresponds substantially to a position where the tool is in a position, either high or low, where there is stoppage of the tool, before or after a movement of the latter, only the fixed clamp 15f is then active. The movable clamp 15m is in the advanced position, that is to say that the clamps 15f, 15m are close to each other. This configuration also corresponds to the end of an advance cycle of the band 5. When the tool 3 starts to descend in the direction of the band, this simultaneously causes a descent of the plate 11, as shown in FIG. In this case, the fingers 22 of the sliders 23 of the fixed clamp 15f move in the slots 13, towards the upper ends 13s thereof. Since the gap between the edges facing the slots 13 is still the same, the sliders 23 have not moved away from each other, being held by the stops 40. They have therefore not caused the bearing to rise. upper jaw 17 of the fixed clamp 15f. Similarly, the fingers 35 of the slides 34 of the upper jaw 31 of the movable gripper 15m are moved towards the upper end 39s of their slot 39 respectively. During this movement, the fingers 35, 37 of the sliders 34 and jaws 30, 31 have followed the curvatures of their slots 38, 39 respectively. These curves being oriented towards the rear of the frame 8, that is to say the left part of Figures 3 to 10, there is rearward displacement of the movable clamp 15m, along the trees 27. In the vicinity of the central zone of the slots 39 where are then the fingers 35, the slots 39 are wider. This facilitates the spacing apart from each other of the slides 34. In other words, by opening the V formed by the bars 33, the upper jaw 31 is brought into contact with the lower jaw 30. The carriage 26 has moved away from the tool 3 to a so-called withdrawn position which corresponds to a so-called low position of the tool 3 during the working phase.

The distance D traversed by the carriage 26, by sliding along the shafts 24, 27, corresponds to a predefined step in advance of the band 5. This distance D corresponds to the maximum distance between an edge of the slot 38, between its lower end 38b and its upper end 38s. In other words, the distance 9 corresponds to the distance traveled by the finger 37 in the curvature of the slot 38. To change the pitch, that is to say the distance D, we can change the frame 8 for a another frame, longer and / or higher with slits of suitable size and shape in order to have races of the slides 34 larger.

In this configuration, there was no contact between the upper and lower jaws 31 of the movable clamp 15m, the bars 33 having maintained a generally constant spacing therebetween, the movable clamp 15m is always in the open position.

Continuing the descent of the tool 3, so the plate 11, is passed through a position where the two clamping members 15f, 15m are open, as shown in Figure 5. This position corresponds to a dead center of the device 7 , the band 5 being stationary and not maintained, the tool 3 being further removed from the part 4 of the band to work.

This position makes it possible to reposition the band 5 perfectly before the work of the tool 3. For this purpose, conical pitons, called pilots, not shown and fixed on the work table 1, fit into orifices, not shown, located in the vicinity of the lateral edges of the band 5. This makes up for any offset of the band during its movement. The presence of these drivers makes it possible to catch a game of the order of 2/100 of a millimeter. During the downward movement of the plate 11, the fingers 35, 37 and the clamp 15m are moved towards the upper end 38s, 39s of their slots 38, 39 respective but the spacing between the slides 34 remained the even, the mobile clamp 15m has remained open, without lateral displacement. On the other hand, the displacement of the fingers 22 of the upper jaw 17 of the fixed clamp 15f has been effected in the direction of the upper ends 13s of the slots 13. The fingers 22 are in the part of the slots 13 where the latter have their edges in look the most apart from each other. This induces an opening of the V formed by the bars 20 and therefore a spacing of the sliders 23. This has the effect of moving the upper jaw 17 towards the top of the frame 8. The fixed clamp 15f is thus in an open position.

The descent of the plate 11 continues to a bottom dead point illustrated in Figure 6. The fingers 22 of the sliders 23 of the upper jaw 17 of the fixed clamp 15f are at the upper end 13s of the slots 13 and therefore in maximum spread position. Indeed, the gap between the slots 13 is maximum at the ends 13s. The fingers 35 of the slides 34 of the upper jaw 31 of the movable gripper 15m are moved towards the upper ends 39s of the slots 39. These ends 39s are narrower than the main part of the slots 39. The gap between the slots 39 is therefore maximum. This has the effect of moving the slides 34 from one another, which has the effect of moving the bars 33 and thus open the V they form. The upper jaw 31 is thus pulled in the direction of the jaw 30, that is to say the band 5. In this so-called withdrawn position, the movable clamp 15m, closed, is removed to the maximum of the tool 3 and the slides 34 are held in position by the stops 40 '. Tool 3 is at its bottom dead point. The piece has been made, the tool will go up to prepare for the realization of a new piece. For this, a non-worked area of the band must be brought under the tool. Thus, from this so-called low dead point position, an upward movement of the plate 11 corresponding to the ascent of the tool 3 begins as shown in FIG. 7. During this ascent, the fixed clamp 15f still remains open since the fingers 22 move towards the lower end 13b of the slots 13 but while maintaining the spacing between the sliders 23. The bars 20 keep the upper jaw 17 away from the lower jaw 16 and thus the fixed clamp 15f open. The rise of the plate causes the fingers 35, 37 of the movable clamp 15m to move in the slots 39, 38 towards the lower ends 39b, 38b, the fingers 35, 37 remaining resting against the walls of the slots 39, 38. As the spacing between the slots 39 is constant, the movable clamp remains closed. As long as the fingers 35 are in the part of the slots 39 located above the curvature, the carriage 26 does not move, the movable clamp 15m remains closed. During the passage of the fingers 35 in the curvature of the slots 39, there is movement of the carriage towards the fixed clamp 15f, that is to say in the direction F2 of advance of the band. Slot 38 being provided with a curvature identical to that of slots 39, the jaws 30, 31 also move in the direction F2, by sliding on the shafts 24, 27. The jaws 30, 31 remain closed and aligned. Indeed, during the displacement, the alignment of the jaws 30, 31 is maintained by the vertical shafts 32 and the finger 37 inserted into the slot 38. The movable clamp 15m moves while remaining closed and the fixed clamp 15f is always open. In this way, the advance of the web 5 is carried out during the ascent phase of the tool 3. The upward movement of the plate 11 continues until the configuration illustrated in FIG. 8. The fingers 22 of the clamp fixed are always in the wide part of the slots 13 and approach the lower terminal 13b. They move from a position where they are still distant from each other to a position where they get closer, the course of this displacement substantially corresponding to the gap between the two high 13s and 13b low end portions of the slots 13 In other words, the fixed clamp 15f remains open but its closing movement is initiated.

In this position, the fingers 35 of the slides 34 of the upper jaw 31 of the movable gripper 15m are moved towards the lower end 39s of the slots 39. The fingers 35 are beyond the curvature, in a vertical part of the slots 39. The carriage 26 is near the fixed clamp 15f, the advance of the band 5 is therefore in the completion phase.

As the spacing between the slits 39 has remained generally constant, the sliders 34 exerted a pull similar to that previously described on the upper jaw 31 of the movable clamp 15m. The movable clamp is held in closed position around the band. The holding in the closed position of the movable clamp 15m is favored by the support of the slides 34 on the stops 40 '. When the advance of the carriage 26 is completed, the upward movement of the plate 11 continues, the fingers 22 and 35 of the slides 23 and 34 of the clamps 15f, 15m are located near the lower portions 13b, 39b of the slots 13, 39 This configuration is illustrated in FIG. 9. The fingers 35 of the mobile clamp 15m are in the straight zone of their slots 39 but have not yet reached the lower end 39b thereof. The spacing of the sliders is constant, since the fingers 35 are always in the wide part of the slots 39. This always corresponds to the closure of the movable clamp 15. The fingers 22 of the sliders 23 of the upper jaw 17 of the fixed clamp 15f are in the lower end portion 13b of the slots 13. In this part, the slots 13 are close together, which allows, by closing the V formed by the bars 20, to push the upper jaw 17 against the strip, towards the jaw fixed 16. The fixed clamp 15f is closed. In this position, the advance of the moving clamp towards the fixed clamp is at the end of the stroke. The fixed clamps 15f and mobile 15m are closed, the device 7 has reached another dead point, just before a return of the carriage 26 in the starting position. The movement of the plate 11 upwards continues until the fingers 22, 35 of the slides 23, 34 of the fixed and movable clamps 15f and 15m abut in the lower ends 13b, 39b of their respective slots 13, 39 as shown in Figure 10. In this position, the plate 11 and therefore the tool 3, have reached their top dead center. The fingers 22 of the fixed clamp 15f are in the same configuration as that shown in Figure 9, the fixed clamp 15f remains closed. The fingers 35 of the movable clamp 15m abut them in the lower end 39b of their slots 39. The ends 39b being narrower than the main part of the slots 39, the fingers 35 are closer together. As a result, the slides 34 of the upper jaw 31 come closer to bearing against the leg of the lower jaw. The V formed by the bars 33 closes and causes the upward movement of the upper jaw 31, sliding along the shafts 32. The mobile clamp 15 is then open. In other words, this position is similar to that of Figure 3. The tool is then ready for a new parts manufacturing cycle. The plate 11 and the clamps 15f, 15m being in the initial position, as illustrated in FIG. 3. The path of the fingers of the sliders 23, 34 in the slots 13, 39 is substantially a hysteresis curve-shaped path, that is to say that the continuation of the movement, after causing a separation of the slides induces the approximation of the latter. Thanks to the slots 13, 39, the spacing of the sliders is regular and controlled. In particular, the movement is guided permanently by the shafts 24, 27 and the fingers 22, 35.

A purely mechanical device is thus produced, which is not dependent on a power supply, and which is directly connected to the machine since the plate 11 follows the movements of the tool 3. The movements of the fixed clamps 15f and the mobile clamp 15m are easily adjustable. . It is possible to provide, for a given device, several sets of 10 plates 11 to have a range of steps in advance of the band 5 defined.

Claims (13)

1. Device for feeding a strip material for feeding a machine tool, equipped at least with a tool (3) movable in a non-parallel direction (F1), in particular perpendicular to a direction of advance (F2 ) of said strip (5), this device comprising at least two clamping members (15f, 15m) of the strip (5) of material, one of the members (15f), said fixed, being adapted to move between an open position and a closed position and one of the members (15m), said mobile, being adapted to move, on the one hand, between an open position and a closed position, and, on the other hand, between an advanced position and a withdrawn position relative to the tool (3), characterized in that it comprises, in addition, at least one actuating member (11), movable, adapted to maneuver during its movement the fixed clamping members (15f) and movable (15m) and in that this operating member (11) is connected by a securing means (12) to the tool (3), in a manner that re a movement of the tool (3) directly induces a displacement of the actuator (11). 2. Feed device according to claim 1, characterized in that the operating member comprises at least one plate (11) provided with at least one guide path (13, 13 ') of the clamping members (15f, 15m). 3. Device according to claim 2, characterized in that the guideways comprise two types of slots (13, 13 ') formed in the plate (11). 4. Device according to claim 3, characterized in that a first type of slots comprises two slots (13) non-rectilinear, S-shaped and arranged in a mirror of one another. 5. Feeder device according to claim 3, characterized in that a second type of slots comprises three non-rectilinear slots (38, 39), configured in S, the distance (D) between the same edge of the lower end. (38b) and the upper end (38s) of some (38) slots (38, 39) corresponding to a step in advance of the strip (5). 6. Device according to claim 1, characterized in that the fixed clamping member is a fixed clamp (15f) formed of a so-called fixed jaw (16) integral with the frame (8) and a so-called mobile jaw (17). ), movable vertically above the fixed jaw (16). 7. Device according to claim 6, characterized in that the upper jaw (17) of the fixed clamping member (15f) is operated by sliders (23) provided with fingers (22) inserted into the slots (13) of the plate (11). 8. Device according to claim 1, characterized in that the movable clamping member is a movable clamp (15m) formed of a lower jaw (30) of T-shaped cross-section, movable in a direction parallel to a direction of rotation. advancing (F2) of the band (5) and an upper jaw (31) moving vertically above the lower jaw (30). 9. Device according to claim 8, characterized in that the upper jaw (31) of the movable clamping member (15m) is operated by sliders (34) provided with fingers (35) inserted into the slots (39) of the plate (11). 10. Device according to one of claims 6 to 8, characterized in that the upper jaws (17, 31) of the fixed clamps (15f) and movable (15m) are connected by bars (20, 33) to the sliders ( 23, 34) movable in translation parallel to a direction of advance (F2) of the band (5), said slides (23, 34) being adapted to manipulate said jaws (17, 31) during their displacement. 11. Device according to claim 10, characterized in that the slides (23,34) are equipped with actuating fingers (22, 35) inserted into the slots (13, 39) of the plate (11) so as to be moved. when the plate moves. 12. Device according to claim 8, characterized in that the lower jaw (30) of the movable clamp (15m) is equipped with fingers (37) inserted into the middle slot (38) of the second type of slots (13 '). 13. Machine tool equipped with a device (7) for advancing a strip material (5) according to one of the preceding claims.