EP0848768B1 - Device for guiding a sewn material perpendicularly to a presser foot, automatic sewing method and sewing machine - Google Patents

Description

The invention relates to a device for guidance of flexible textile material (fabric, knitting, etc.) likely to be sewn on a type sewing machine traditional comprising a work-holding plate and a material feed claw mechanism, associated with minus a needle; thereafter this mechanism and its accessories will be designated by the expression "presser foot". The invention extends to an automatic sewing process for material, implemented using a sewing machine equipped with such a guide device. She's spreading also to advanced sewing machines equipped one or more guidance devices conforming to the invention.

In the garment industry, the operations of sewing pieces of fabric or knitting are generally aimed at sew two pieces together along one of their edges or hemming a piece, or fix along an edge of a piece a ribbon, an elastic, a belt, etc ... To try to save money of labor and productivity gains, we proposed guidance systems that move the fabric or knit in the transverse direction upstream of the needle in order to constantly bring the sewing area in front of the needle; these systems generally include wheels or tracks on casters, arranged in the direction transverse upstream of the needle in the direction which are rotated in a either way so you can move transversely (perpendicular to the direction material) in both directions so perform the appropriate position corrections. However, these systems are little used because they lead to imperfect seams and defects common. Indeed, the flexible material driven by the presser foot at the needle is braked upstream of it by the guidance system, and tends to roll on itself, crease or pucker so random, which is incompatible with obtaining a regular quality sewing; this defect is particularly serious for stretch knitwear or "to soft stitches "that cannot be sewn with these known systems; in the case of two parts to be assembled edge to edge, there are shifts from one edge to the other relationship to each other and assembly imperfections detrimental to the quality of the product produced. In addition, the most existing systems can only be used for materials of defined thickness.

Subsequently, (patents FR 2,585,683 and EP 0.216.644) a guide device has been proposed which includes a spherical wheel bearing against the material upstream of the presser foot and rotating in a single direction of rotation to ensure drive and guidance material upstream of the sewing area. These measures is of a principle radically different from the others previous systems insofar as, in these patents, the spherical wheel is laterally offset, drives the material in the same direction as the presser foot, but is pivotally mounted around a vertical axis so as to to be able to orient it thanks to an analog type control proportional according to training directions different to bring the material into the desired position. In the device covered by these patents, the spherical wheel is rotated by friction by a roller which comes to rest on one side of this in the horizontal plane containing the axis of said wheel.

However, such a system faces a serious practical difficulty of implementation. To allow a satisfactory drive of the spherical wheel by the roller, it is necessary that the surfaces of these bodies roll without sliding against each other and have therefore a sufficient coefficient of friction; when the spherical wheel rotates around the vertical axis to adopt another orientation, the support of the roller on this wheel describes a large circle segment and this movement is transverse to the roller (parallel to the axis of the roller and perpendicular to the tangential speed), so the friction of the two surfaces tends to oppose movement. Under these conditions, the swivel of the spherical wheel to modify its orientation require the use of significant forces, must be slow in relation to the rotational speeds of the roller and wheel, and produce rapid wear of the surfaces which constrains frequent changes of these organs.

To overcome these drawbacks, EP-A-0 468 578 then proposed a guide device the roller of which is positioned above a member adjustment turn by entrainment of the material (sphere elastic) so as to come into contact with the area upper of said rotating member opposite the area of contact of said member with the material, the support zone of said roller with said rotating member being substantially located on the vertical axis around which the pivoting of said rotating member. So the material is longitudinally driven by the rotating member, so permanent, at a point of contact on the right upstream of the presser foot, and position corrections are made by orienting appropriate the direction of this training.

This system is satisfactory, but is nevertheless limited to guiding parts parallel to reference lines whose radius of curvature is important, especially greater than about 25 cm. So, this system is not in practice fast enough and efficient to make automatic seams parallel to lines with very pronounced curvature portions (radius of curvature less than 25 cm), even angular. Of such seams must therefore still be made manually by operators who guide the material in front and upstream of the needle.

It should be noted that in the known guidance, we have so far sought to automate the operator's action by guiding the material immediately upstream of the needle. So in all above-mentioned guiding devices with rotating member spherical, we adjust the position of the material by making vary the orientation angle of the axis of rotation by the organ rotating in one direction or the other.

In addition, it is considered up to now as inevitable, in these devices that the material cannot be guided continuously provided between the adjustment member and the presser foot, that is to say over a distance that can extend in practice over several centimeters.

Furthermore, FR-2,392,909 describes a device comprising several rotating rollers around a common fixed axis perpendicular to the direction drive and passing through the needle. The different motors of the different rollers are controlled by a analog control which applies voltages to them that the pivot center applied by all of these pebbles coincides with the center of curvature of the edge of the sewn piece of fabric. This device is not conceivable only with large pieces and leads in practice to numerous untimely wrinkling phenomena, especially in the case of flexible or stretchy fabrics. In Besides, it is complex, extremely delicate, if not impossible to settle satisfactorily, and requires adjustments with each change of fabric and / or shape of room.

US-4,813,364 describes an endless strip arranged laterally in contact along a linear surface contact parallel to the direction of training. Such device is totally ineffective in practice since the strip in contact with the fabric prevents pivoting or induces significant wrinkling of the tissue.

The invention therefore aims to resolve these disadvantages by proposing a device for guiding a material to be sewn parallel to a reference line, in particular an edge of the material, which may have any curvatures, and in particular strong curvatures or even angles. The invention aims at especially the realization of automatic seams which can have radius of curvature significantly less than 25 cm, in particular which can take any value between a centimeter or a few centimeters, and 25 centimeters.

The subject of the invention is the mounting of one or many of these devices perfected on a machine sewing type known per se (with a work-holding plate and a presser foot associated with at least one needle) to allow sewing so automatic pieces of material parallel to a predefined reference line, constituted in particular by an edge of the pieces. The invention applies whatever or the purpose of sewing: sewing a ribbon, a belt, elastic at the edge of the piece, seam a hem (the machine being provided with a device classic material folding), two-piece sewing together (the machine being provided with two guide) ...

The objective of the invention is to allow obtaining a regular seam of good quality, high cadence, including in the case of strong curvatures, whatever the material (especially knitwear or fabrics thin, difficult to handle, stretch materials ...), and this, by eliminating the difficulties of implementation (such as phenomena of untimely wrinkling) to which collide with previous devices.

Another objective is to provide a simple structure guiding device, which, mounted on a traditional type sewing machine, allows make automatic seams on materials of any thickness, parallel to lines any, with pieces of any shape.

Thus, the invention relates more particularly to propose a guidance device making it possible to achieve both concave and convex curvatures (i.e. in both directions).

The invention further aims to provide a such a device which does not require complex adjustments to each change of material and / or shape of part, and therefore has great versatility.

The invention aims even more particularly to provide a guidance device to guide the material from the start of sewing and until the end of the seam of the piece of material.

The invention aims in particular to propose a guiding device for automatic sewing underwear (thongs, bras, tank tops, t-shirts, briefs, ...).

• "matériau" : tout matériau souple textile en nappe, y compris tissu, tricot... susceptible d'être cousu,
• direction "longitudinale" : direction de la ligne de couture désirée,
• direction "transversale" : direction perpendiculaire à la direction longitudinale,
• direction "verticale" : direction orthogonale à la nappe de matériau (ou à la plaque porte-ouvrage de la machine à coudre, qui porte le matériau), au niveau du pied-presseur,
• direction "horizontale" : direction parallèle à la nappe de matériau (ou à la plaque porte-ouvrage de la machine à coudre), au niveau du pied-presseur,
• "pied-presseur" : ensemble du mécanisme classique assurant le guidage et l'avance du matériau au niveau de l'aiguille,
• "amont" et "aval" sont utilisés en référence au sens d'entraínement de la pièce de matériau par le pied-presseur,
• "au droit de..." : aligné selon une direction transversale avec...,
• "droite d'entraínement" : droite parallèle à la direction longitudinale d'entraínement par le pied-presseur et passant par le pied-presseur.

Certain terms used subsequently in order to simplify the terminology and make the description clearer are defined below:

• "material": any flexible textile textile material, including fabric, knitted fabric ... capable of being sewn,
• "longitudinal" direction: direction of the desired seam line,
• "transverse" direction: direction perpendicular to the longitudinal direction,
• "vertical" direction: direction orthogonal to the sheet of material (or to the work-holding plate of the sewing machine, which carries the material), at the presser foot,
• "horizontal" direction: direction parallel to the sheet of material (or to the work-holding plate of the sewing machine), at the presser foot,
• "presser foot": assembly of the conventional mechanism ensuring the guidance and the advance of the material at the level of the needle,
• "upstream" and "downstream" are used with reference to the direction of drive of the piece of material by the presser foot,
• "at the right of ...": aligned in a transverse direction with ...,
• "drive straight": straight line parallel to the longitudinal direction of drive by the presser foot and passing through the presser foot.

The invention therefore relates to a method of automatic sewing of a piece of flexible textile material (fabric, knitting ...) using a sewing machine, in which at least one organ is permanently applied rotary adjustment in contact with the material in at least one contact point on the material laterally offset from the drive right, characterized in that one applies the adjustment member at at least one point of contact located, in operation, at least substantially at the level of the presser foot, and as you go up, you apply the organ adjustment and it is kept permanently applied to the contact of the material so that, in operation, a plane perpendicular to the work plate at the point of contact and which contains the speed direction peripheral V1 of the adjustment member at the point of contact, form with a plane perpendicular to the plate book holder at the point of contact and parallel to said training right, an angle α of fixed orientation no no.

According to the invention, the angle α of orientation is less than 90 °, in particular between 20 ° and 45 °.

Advantageously, and according to the invention, one mount the adjustment member on the machine and apply it at a point of contact located so that a plane vertical which contains a straight line passing through the point of contact and through the entry of the presser foot forms an angle β of the order of 90 ° with a vertical plane which contains the training right.

• on place et on maintient l'organe d'ajustement dans l'un des deux états suivants, en fonction de la valeur du signal de position : un état entraíné en rotation en sens direct ; et un état freiné,
• à l'état entraíné en sens direct, on entraíne l'organe d'ajustement à une vitesse correspondant à une vitesse périphérique V1 de l'organe d'ajustement au point de contact qui est supérieure à la composante V2", au point de contact et selon la direction de ladite vitesse périphérique V1, de la vitesse d'entraínement V2 du matériau par le pied-presseur,
• à l'état freiné, on commande l'entraínement de l'organe d'ajustement pour que ladite vitesse périphérique V1 soit inférieure ou de sens opposé à ladite composante V2" de la vitesse d'entraínement V2 du matériau par le pied-presseur,
• on place et on maintient l'organe d'ajustement à l'état entraíné en rotation en sens direct lorsque ledit point de contact et ladite ligne prédéfinie de référence sont de part et d'autre d'une ligne droite, dite ligne de détection, passant par le détecteur et parallèle à la droite d'entraínement, ce par quoi le matériau est accéléré, audit point de contact, par l'organe d'ajustement, et donc entraíné en pivotement dans un sens F1 par rapport à la plaque porte-ouvrage,
• et on place et on maintient l'organe d'ajustement à l'état freiné lorsque ledit point de contact et ladite ligne prédéfinie de référence sont situés du même côté de la ligne de détection, ce par quoi le matériau est freiné, audit point de contact, par l'organe d'ajustement, et donc entraíné en pivotement dans l'autre sens F2 par rapport à la plaque porte-ouvrage.

The invention further relates to a method in which the transverse position of a predefined reference line of the material is detected in a detection zone upstream of the presser foot and a position signal is generated whose value varies according to whether said predefined reference line is on one side or the other of a straight line, said detection line passing through the detection zone and parallel to the drive line,
characterized in that:

• we place and maintain the adjustment member in one of the following two states, depending on the value of the position signal: a state driven in rotation in the forward direction; and a braked state,
• in the directly driven state, the adjustment member is driven at a speed corresponding to a peripheral speed V1 of the adjustment member at the contact point which is greater than the component V2 ", at the contact point and in the direction of said peripheral speed V1, of the speed of drive V2 of the material by the presser foot,
• in the braked state, the drive of the adjustment member is controlled so that said peripheral speed V1 is less than or in the direction opposite to said component V2 "of the speed of drive V2 of the material by the presser foot,
• the adjustment member is placed and maintained in the state driven in rotation in the forward direction when said contact point and said predefined reference line are on either side of a straight line, called detection line, passing through the detector and parallel to the drive line, whereby the material is accelerated, at said contact point, by the adjustment member, and therefore driven in pivoting in a direction F1 relative to the carrier plate work,
• and the adjustment member is placed and maintained in the braked state when said contact point and said predefined reference line are located on the same side of the detection line, whereby the material is braked, at said point of contact, by the adjustment member, and therefore driven in pivoting in the other direction F2 relative to the work-holding plate.

• on détecte la présence ou l'absence de matériau en au moins une zone de détection située immédiatement à l'amont, et de préférence à proximité immédiate du pied-presseur, sur la trajectoire prévue du bord à détecter,
• on génère un signal de position à deux états représentatifs de la présence ou de l'absence de matériau,
• on commande le changement d'état de l'organe d'ajustement alternativement de l'état entraíné en sens direct à l'état freiné, ou inversement, selon l'état et à chaque changement d'état du signal de position.

The method according to the invention is more particularly applicable to the execution of an automatic sewing of a piece of material along one of its edges constituting a predefined reference line, and is characterized in that:

• the presence or absence of material is detected in at least one detection zone located immediately upstream, and preferably in the immediate vicinity of the presser foot, on the intended path of the edge to be detected,
• a position signal is generated with two states representative of the presence or absence of material,
• we order the change of state of the adjustment member alternately from the directly driven state to the braked state, or vice versa, depending on the state and each time the state of the position signal changes.

With a method according to the invention, performs both convex and concave curves and the guidance is provided to the end of the workpiece material. In addition, the adjustment of the material takes place on the portion of material engaged in the presser foot and is controlled by a detection carried out immediately at upstream and near the presser foot, so that eliminates any area of no guidance of the material to be the upstream of the presser foot and the reaction times are longer fast.

Thus, although the adjusting member does not either not upstream of the presser foot, which was considered as essential in the devices of the prior art (in which the principle was to guide the piece of material before it passes under the presser foot), we with the invention obtains guidance on all the material entering the presser foot with greater efficiency and with greater precision at the presser foot.

Furthermore, according to the invention, it is the position of the portion of the reference line that passes to the right of the detection area, which we use to determine whether to place the adjuster in one or the other of the states. Furthermore, when this portion of the reference line passes exactly over the area of detection and coincides with the detection line we can choose to place and maintain the adjusting member in either of the two states. We choose for example the state driven in a direct sense.

Although the point of contact of the organ adjustment is not placed on the drive line and that the orientation of the adjustment member remains fixed, it appeared that with a simple piloting of the all or nothing done continuously and at high frequency, we achieves high-precision adjustment and guidance according to curves which can be very strong curvature, even angular. Several explanations can be advances in the observation of this result: the couple of pivoting induced by the guide device is at least approximately proportional to the distance between the contact point and presser foot entry, distance which may be significant and no longer affects the effectiveness of the guidance as in the previous devices; of them separate phenomena are used respectively in two states: in the braked state, it is the presser foot itself which causes the material to pivot around a center of rotation passing through the point of contact, and at the state driven in the direct direction the pivoting is due to the speed difference between the material training at point of contact by the adjuster and the material drive at the presser foot; the non-zero fixed orientation angle α laterally stretches the material permanently between the point of contact and the presser foot, which greatly increases the dynamic performance avoiding any phenomenon untimely unwanted (puckering, wave effects, ...).

In the braked state, it suffices that the organ adjustment brakes the material at the point of contact so that it pivots. Advantageously and according to the invention, the adjustment member is blocked to stop it in the braked state. Indeed, a stop command is particularly simple and quick to implement.

If increased pivoting efficiency (i.e. a smaller radius of curvature) is desired, we can even train the adjustment member retrograde direction (opposite to direct direction) in the braked state. In this case, the material is caused to retreat locally at the point-of-contact.

Advantageously and according to the invention, for control the functioning and state of the organ adjustment, we drive a drive motor in all or nothing by applying it, either a training signal in direct direction, i.e. a braking signal, depending on whether detect or not the presence or absence of material.

The invention also relates to a device for material guidance, for the implementation of the process according to the invention.

• au moins un organe d'ajustement de la position transversale du matériau, monté rotatif et de façon à pouvoir venir au contact du matériau, et adapté pour pouvoir modifier localement la vitesse d'entraínement du matériau lorsqu'il est appliqué sur le matériau,
• des moyens d'application de l'organe d'ajustement en permanence au contact du matériau en un point de contact décalé latéralement d'une droite, dite droite d'entraínement passant par le pied-presseur et parallèle à la direction longitudinale d'entraínement,

caractérisé en ce que les moyens d'applications sont adaptés et l'organe d'ajustement est monté de façon que :

• ledit point de contact soit situé, en fonctionnement, au moins sensiblement au droit du pied-presseur,
• en fonctionnement, un plan perpendiculaire à la plaque porte-ouvrage au point de contact et qui contient la direction de la vitesse périphérique V1 de l'organe d'ajustement au point de contact, forme avec un plan perpendiculaire à la plaque porte-ouvrage au point de contact et parallèle à ladite droite d'entraínement, un angle α d'orientation fixe non nul.

The invention thus relates to a device for guiding flexible textile material (fabric, knitted fabric) capable of being sewn, fitted to a sewing machine provided with a work-holding plate, and a presser foot for driving of the material in a longitudinal direction of drive associated with at least one needle, in order to allow the execution of an automatic sewing of the material, this guide device comprising:

• at least one member for adjusting the transverse position of the material, mounted so as to be able to come into contact with the material, and adapted so as to be able to locally modify the speed of entrainment of the material when it is applied to the material,
• means for applying the adjustment member permanently in contact with the material at a contact point offset laterally by a straight line, called the drive straight passing through the presser foot and parallel to the longitudinal drive direction ,

characterized in that the application means are adapted and the adjustment member is mounted so that:

• said point of contact is located, in operation, at least substantially at the level of the presser foot,
• in operation, a plane perpendicular to the work plate at the point of contact and which contains the direction of the peripheral speed V1 of the adjustment member at the point of contact, forms with a plane perpendicular to the work plate at contact point and parallel to said drive line, a non-zero fixed angle α.

Advantageously and according to the invention, the orientation angle α is less than 90 °, in particular between 20 ° and 45 °.

The expression "at least substantially at presser foot right "means that the point of contact is located in an area which is neither fully upstream nor fully downstream of the presser foot. In other words, a plan perpendicular to the work plate and to the direction which contains the contact point, passes by the presser foot.

Advantageously and according to the invention, the adjusting member is also applied and mounted so that a plane which contains a straight line passing through the point of contact and through the entry of the presser foot forms an angle β of the order of 90 ° with a vertical plane which contains the training right.

In addition, the device according to the invention advantageously comprises means for prior adjustment of the position of the adjustment member relative to the presser foot.

• des moyens d'entraínement à partir d'un mouvement moteur généré par un moteur, de l'organe d'ajustement en rotation au moins dans un sens, dit sens direct, pour lequel la vitesse périphérique V1 de l'organe d'ajustement au point de contact présente une composante V1' selon la direction d'entraínement qui est orientée dans le sens d'entraínement du matériau par le pied-presseur,
• un détecteur de la position transversale de ladite ligne prédéfinie de référence, -notamment sous la forme d'un détecteur de présence ou d'absence de matériau-associé à des moyens de génération d'un signal de position dont la valeur varie selon que ladite ligne prédéfinie de référence est d'un côté ou de l'autre d'une ligne droite, dite ligne de détection, passant par le détecteur et parallèle à la droite d'entraínement.

The guiding device according to the invention is advantageously applicable for the execution of an automatic sewing of a piece of material along a predefined reference line, for example along one of its edges. It then includes:

• drive means from a motor movement generated by a motor, of the adjusting member in rotation at least in one direction, called direct direction, for which the peripheral speed V1 of the adjusting member at contact point has a component V1 'in the direction of drive which is oriented in the direction of drive of the material by the presser foot,
• a detector of the transverse position of said predefined reference line, in particular in the form of a presence or absence detector of material-associated with means for generating a position signal, the value of which varies according to whether said predefined reference line is on one side or the other of a straight line, said detection line, passing through the detector and parallel to the drive line.

• en ce que les moyens d'entraínement sont adaptés pour pouvoir entraíner l'organe d'ajustement en sens direct à une vitesse périphérique V1 de l'organe d'ajustement au point de contact qui est supérieure à la composante V2", au point de contact et selon la direction de ladite vitesse périphérique V1, de la vitesse d'entraínement V2 du matériau par le pied-presseur,
• en ce que les moyens d'entraínement de l'organe d'ajustement sont adaptés pour placer et maintenir l'organe d'ajustement dans l'un des états suivants : un état, dit état entraíné en sens direct, où il est entraíné, à ladite vitesse périphérique V1 en sens direct par les moyens d'entraínement ; et un état, dit état freiné, où ladite vitesse périphérique V1 est inférieure ou en sens opposé à ladite composante V2" de la vitesse d'entraínement V2 du matériau par le pied-presseur,
• et en ce qu'il comporte des moyens de commande de type tout ou rien adaptés pour commander les moyens d'entraínement en fonction de la valeur dudit signal de position :
  • à l'état entraíné en sens direct de l'organe d'ajustement lorsque ledit point de contact et ladite ligne prédéfinie de référence sont de part et d'autre de la ligne de détection, ce par quoi le matériau est accéléré, au point de contact, par l'organe d'ajustement et donc entraíné en pivotement dans un sens F1 par rapport à la plaque porte-ouvrage,
  • à l'état freiné de l'organe d'ajustement lorsque ledit point de contact et ladite ligne prédéfinie de référence sont situés du même côté de la ligne de détection, ce par quoi le matériau est freiné, audit point de contact, par l'organe d'ajustement et donc entraíné en pivotement dans l'autre sens F2 par rapport à la plaque porte-ouvrage.

The device according to the invention is characterized:

• in that the drive means are adapted to be able to drive the adjustment member in the direct direction at a peripheral speed V1 of the adjustment member at the contact point which is greater than the component V2 ", at the point of contact and in the direction of said peripheral speed V1, of the speed of drive V2 of the material by the presser foot,
• in that the means for driving the adjustment member are adapted to place and maintain the adjustment member in one of the following states: a state, known as a directly driven state, where it is driven, at said peripheral speed V1 in the direct direction by the drive means; and a state, called braked state, where said peripheral speed V1 is lower or in the opposite direction to said component V2 "of the speed of drive V2 of the material by the presser foot,
• and in that it includes all or nothing type control means suitable for controlling the drive means as a function of the value of said position signal:
  • in the directly driven state of the adjustment member when said contact point and said predefined reference line are on either side of the detection line, whereby the material is accelerated, to the point of contact, by the adjustment member and therefore driven in pivoting in a direction F1 relative to the work-holding plate,
  • in the braked state of the adjustment member when said contact point and said predefined reference line are located on the same side of the detection line, whereby the material is braked, at said contact point, by the adjustment member and therefore rotated in the other direction F2 relative to the book holder plate.

According to one embodiment particularly simple and advantageous, the means drive include a drive motor, and said control means comprise a circuit electronic control in all or nothing suitable for deliver to the engine, a drive signal in the direction direct from the motor corresponding to the driven state in direction direct from the adjustment device, i.e. a braking signal of the motor corresponding to the braked state of the member adjustment, according to the state of said position signal. In variant or in combination, the drive means include means for clutching / disengaging the member adjustment with respect to said motor movement.

Advantageously and according to the invention, the device according to the invention comprises means for braking of the adjustment member adapted to block the adjustment member in the braked state. In particular, according to the invention, the control means are adapted for ability to control shutdown of state adjuster braked.

Advantageously and according to the invention, the guide device is characterized in that the means are adapted to be able to also train the retrograde adjustment member opposite to the direction direct.

Advantageously and according to the invention, the device comprises means for prior adjustment of the angle of orientation, so as to allow adjustment initial, in particular depending on the nature and characteristics of the material, and shapes of the line of reference.

In addition, the device according to the invention advantageously comprises means for prior adjustment of the position of the adjustment member relative to the presser foot.

According to an advantageous embodiment, and according to the invention, the guide device is characterized in that the adjustment member is of the rotary type (wheel) and mounted free in rotation around an axis and in that the drive means include a driving member capable of be coupled in rotation to the adjusting member at least in the directly driven state, and means for drive this organ leading in direct rotation to from a motor movement, at a speed of rotation corresponding to said peripheral speed of the organ adjustment.

Advantageously and according to the invention, the driving member is a roller mounted to rotate around a axis so that it can be placed in abutment against the adjustment member with a view to driving it in rotation by friction contact. This roller is for example coupled said drive motor of the controlled adjustment member in all or nothing. According to the invention, the roller and the member are then advantageously adapted for have a sufficiently low rotational inertia to do not drive the motor in direct rotation when a signal to stop or change direction rotation, is applied to the motor. For example, the roller is made of light alloy, in particular aluminum alloy, and has recesses to lighten it. In this way, we prevents the motor from being driven by inertia during braked passages which take place at high speed (on the order of ten or more times per second). This feature is particularly useful in the case of a stepper motor.

• le détecteur de position est un détecteur de présence ou d'absence de matériau, associé à des moyens de génération d'un signal de position à deux états représentatifs de la présence ou de l'absence de matériau,
• les moyens de commande sont adaptés pour commander les moyens d'entraínement alternativement de l'état entraíné en sens direct à l'état freiné ou inversement à chaque changement d'état du signal de position. Avantageusement et selon l'invention, le détecteur et l'organe d'ajustement sont disposés de telle sorte que le point de contact et la ligne de détection sont situés de part et d'autre de ladite droite d'entraínement.

The guide device according to the invention is advantageously applicable for the execution of an automatic sewing of a piece of material along one of its edges constituting said predefined reference line. It is then characterized in that:

• the position detector is a presence or absence detector of material, associated with means for generating a position signal with two states representative of the presence or absence of material,
• the control means are adapted to control the drive means alternately from the directly driven state to the braked state or vice versa at each change of state of the position signal. Advantageously and according to the invention, the detector and the adjustment member are arranged so that the contact point and the detection line are located on either side of said drive line.

In addition, advantageously and according to the invention, the device comprises blowing means material upstream of the presser foot, arranged so that a draft can be applied to the material antagonistic effect to the entrainment of the material induced by the body of adjustment to the state driven in the direct direction. Of this avoids wrinkling of the material likely disturb the functioning of the detector.

The invention also relates to a sewing, especially an industrial sewing machine automatic, for example for assembling parts of finish of neck, sleeves, leg ..., characterized in that it comprises at least one guiding device according to the invention.

The invention also relates to a method, a guide device and a machine comprising combination of all or some of the characteristics mentioned above or below.

• la figure 1 est une vue schématique partielle en perspective vue selon un premier angle d'un dispositif de guidage et d'une machine selon l'invention,
• la figure 2 est une vue schématique partielle en perspective vue selon un deuxième angle d'un dispositif de guidage et d'une machine selon l'invention,
• la figure 3 est une vue schématique partielle en élévation d'un dispositif de guidage selon l'invention en position de fonctionnement,
• la figure 4 est une vue schématique de dessus illustrant la position et l'orientation d'un organe d'ajustement d'un dispositif de guidage selon l'invention, en fonctionnement,
• la figure 5 est une vue schématique de dessus similaire à la figure 4, illustrant l'exécution d'une couture automatique le long d'un bord concave d'une pièce de matériau,
• la figure 6 est une vue schématique de dessus similaire à la figure 4, illustrant l'exécution d'une couture automatique à angle concave d'une pièce de matériau,
• la figure 7 est une vue schématique de dessus similaire à la figure 4, illustrant l'exécution d'une couture automatique le long d'un bord convexe d'une pièce de matériau,
• la figure 8 est une vue schématique de dessus similaire à la figure 4, illustrant l'exécution d'une couture automatique à angle convexe d'une pièce de matériau,
• la figure 9 est un schéma fonctionnel des moyens de commande d'un dispositif de guidage selon l'invention.

Other characteristics, objects and advantages of the invention appear from the description which follows with reference to the appended drawings which represent, without limitation, one of its embodiments, and in which:

• FIG. 1 is a partial schematic perspective view seen from a first angle of a guide device and of a machine according to the invention,
• FIG. 2 is a partial schematic perspective view seen from a second angle of a guide device and of a machine according to the invention,
• FIG. 3 is a partial schematic view in elevation of a guide device according to the invention in the operating position,
• FIG. 4 is a schematic top view illustrating the position and orientation of an adjustment member of a guide device according to the invention, in operation,
• FIG. 5 is a schematic top view similar to FIG. 4, illustrating the execution of an automatic sewing along a concave edge of a piece of material,
• FIG. 6 is a schematic top view similar to FIG. 4, illustrating the execution of an automatic seam at a concave angle of a piece of material,
• FIG. 7 is a schematic top view similar to FIG. 4, illustrating the execution of an automatic sewing along a convex edge of a piece of material,
• FIG. 8 is a schematic top view similar to FIG. 4, illustrating the execution of an automatic seam at a convex angle of a piece of material,
• Figure 9 is a block diagram of the control means of a guide device according to the invention.

The guide device 1 shown in Figures 1 to 8 is mounted on a sewing machine 2 of the type head to the left; traditionally, this machine includes a frame 3, a work plate 4, a presser foot 5 associated with a needle 6 with their kinematics classic drive (feed mechanism with claws ...), means of distributing the wires ... The example referred to for the purpose of sewing an elastic band of collar E in border of a piece P of knitting or other flexible material textile and the machine is equipped with conventional means feeding and guiding this elastic tape E towards the sewing area (not shown). Presser foot 5 is suitable for driving the piece of material into the longitudinal direction, along a drive line 18.

The guiding device according to the present invention is intended to guide the workpiece material P which rests on the work-holding plate 4 in order to allow the realization without the help of an operator of a seam parallel to the edge of the material which can be strong curvature, even angular, convex or concave.

This guide device 1 is carried by a pneumatic cylinder 7 whose body is secured by means of a part 8 on the frame 3 of the machine and whose rod mobile is secured by its end to a support bracket 9 of the guide device. The cylinder 7 is arranged to be able to move the guide device between a working position where it is applied in contact with the material to guide it, and an inactive position where it is away from the material and the work plate 4 of so as to allow in particular the introduction of a new piece of material under the presser foot 5.

In the embodiment shown on the figures, the work-holding plate 4 is formed of a horizontal plate, and the cylinder 7 extends vertically to move the guide device down to the contact of the material to be guided. It is nevertheless understood that the invention extends to other embodiments, including including those where the book holder plate 4 could include an inclined or vertical portion and where the guide device would be applied in contact with this portion, the jack 7 then being inclined or even horizontal. Likewise, the guide device can be placed under the book holder plate 4, or duplicated to achieve a simultaneous guidance of two layers of material, one above it, the other below the plate 4.

The support bracket 9 carries a member adjustment 10 which is mounted and adapted for, in position of the guide device, be applied to the contact of the material at a point of contact 12. This point of contact 12 is located above the work-holding plate or, more generally, on a straight line normal to the book holder plate. The application cylinder 7 applies and permanently maintains the adjusting member 10 in contact of the material, that is to say throughout the duration of the sewing of piece P. Advantageously and according to the invention, this adjustment member 10 is of the rotary type and mounted free in rotation around a horizontal axis XX ', that is to say more generally parallel to the work-holding plate 4. The axis XX 'and the adjusting member 10 are carried by the support bracket 9. The adjusting member 10 advantageously consists of a wheel, for example a sphere of elastic material such as a hollow ball in rubber, mounted (for example by bonding a cap lateral of its surface) on a carrier shaft 11 which journalled relative to a bearing carried by the support bracket 9 so that this spherical wheel 10 is free to rotate around the axis XX 'which passes through its center.

Such an adjustment member 10 comes to material contact at a point of contact 12 belonging to a generator of circular drive located in a plane perpendicular to the work plate 4 and to the axis XX 'of rotation.

The support bracket 9 also carries a leading organ 13 able to be associated with the organ adjustment 10 in order to drive it in rotation. This the driving member 13 is advantageously a mounted roller rotatable around a horizontal ZZ 'axis parallel to the axis XX 'so that it can be placed in abutment against the adjustment member 10 for driving it in rotation by friction contact. The roller 13 is carried by a motor shaft 14 of an electric motor 15, the assembly being carried by the support bracket 9.

Advantageously, the motor 15 is a motor electric type step by step. When the engine 15 is supplied with electrical energy, it rotates the roller 13 which, itself, drives the sphere 10 in rotation around its axis XX 'by friction contact.

The guiding device according to the invention also includes an optical line detector 16 predefined reference that automatic sewing must to follow. This detector 16 is of conventional type, and comprises a block 16a light transmitter / sensor and a reflective plate 16b carried by the work-carrying plate 4 immediately upstream of the presser foot 5. The light source of the transmitter / sensor assembly 16a emits a light ray which is reflected by the plate 16b. The sensor of the transmitter / sensor assembly 16a delivers a electrical signal whose value depends on the intensity light reflected by the plate 16b. So in the absence of material opposite this plate 16b, the electrical signal is maximum, all light being reflected back to the sensor. In the presence of material, the light is absorbed and is not reflected, and the signal electrical output from the sensor is minimum. So the sensor, which is for example a photoelectric cell, delivers an electrical signal whose value varies depending on whether the edge of the material covers the plate 16b or at otherwise do not cover it. In this way, the detector 16 detects the transverse position of the edge at sew the piece of material, this edge constituting said predefined reference line.

The position detector 16 is therefore a presence or absence of material detector, and the photoelectric sensor constitutes generation means of a position signal with two representative states of the presence and absence of material next to the plate 16b.

With this detector 16, the presence or absence of material in at least one zone of detection 16b defined by the plate 16b, located immediately upstream and close to the presser foot 5, on the planned path of the edge to be detected. The brochure 16b is preferably arranged as close as possible to entry 21 of the presser foot 5. Advantageously, the optical detector 16 - and more particularly the plate 16b- is associated with means for adjusting its position transverse in order to adjust the position of the seam in relation to the edge of the material.

The detector 16 makes it possible to detect whether a portion of the edge of the material that passes next to the area detection 16b is on one side or the other of a line, said detection line 17, parallel to the right 18 and which passes through the detection zone 16b.

Instead of detecting the presence or the absence of the sewing edge of the material, it is possible, in variant not shown, to use, with a device for guidance according to the invention, a position detector cross of another predefined reference line, by example a reflective line drawn on the piece of material.

Anyway, detector 16 is mounted upstream of the presser foot 5 and is associated with means for generating (photoelectric cell) a signal position whose value varies depending on whether the point of intersection I of the predefined reference line with a straight line perpendicular to the detection line 17 and passing through the detection zone 16b (i.e. by the reflective plate 16b) is on one side or the other of the detection line 17. The position of the point of intersection I indeed represents the position transverse from the edge of the piece of material opposite the detection zone 16b, on one side or the other of the detection line 17.

As seen in Figure 4, the detector 16 and the adjusting member 10 are arranged so that the contact point 12 and the detection line 17 are located on either side of the drive line 18.

The signal from detector 16 is supplied to a control circuit 19 (FIG. 9) of the motor 15.

The vector V2 represents the speed of the piece of material by the presser foot 5. At the point of contact 12, this training induces a training speed represented by the vector V2 '. The motor 15 and roller 13 form means of the adjustment member 10, and are adapted to be able to drive this adjustment member 10 in direction direct for which the peripheral speed of this organ 10 at the point of contact 12, represented by the velocity vector V1, has a component parallel to the drive line 18, represented by the vector V1 ', which is oriented in the same direction as the direction material drive by the presser foot 5, that is to say in the same direction as the speed vector V2 material drive by the presser foot 5 (Figures 5 and 6). These drive means 13, 15 are also adapted to drive the adjustment member 10 in direction direct at a rotation speed corresponding to a peripheral speed V1 of this adjustment member 10 of which the value is greater than the component represented by the vector V2 "of the drive speed V2, at the point of contact 12 and in the direction of said speed peripheral V1. More specifically, at the point of contact 12, the adjustment member 10 driven in the direct direction locally accelerates the material with respect to the speed at which it is driven by the presser foot 5 and this acceleration is sufficient to generate a couple of pivoting according to arrow F1 (Figure 5).

It should be noted that for this pivoting according to F1 is obtained, it suffices that V1 'is greater than V2 'in the example shown in Figure 5 where the point of contact 12 is to the right of presser foot 5. More generally, it suffices that the components V1 ', V2' at point of contact 12 of the peripheral speed V1 of the adjusting member 10 and the drive speed V2 by the presser foot 5 along a straight line perpendicular to the straight line connecting point of contact 12 and the presser foot 5, such that V1> V2 '(or V1> V2 ", V2" being the component of V2 'in the direction of V1).

Motor 15 and roller 13 form also training means which are adapted for place and maintain the adjustment member 10 either in the state driven in direct direction at said peripheral speed V1, either in a state, called braked state, where the speed device V1 is lower or opposite to said component V2 "of the material drive speed by the presser foot 5. In the case of the use of a 15 step electric motor, for example, send a signal to the engine 15 commanding its training at a lower speed, or even stopping or its training at a speed in retrograde direction, opposite in the direct sense (Figures 7 and 8).

• à l'état entraíné en sens direct de l'organe d'ajustement 10 lorsque la ligne prédéfinie de référence et le point de contact 12 sont de part et d'autre de la ligne de détection 17, ce par quoi le matériau est accéléré au point de contact 12 par l'organe d'ajustement 10, et donc est entraíné en pivotement dans un sens (flèche F1 figures 5 et 6) par rapport à la plaque porte-ouvrage 4,
• à l'état freiné de l'organe d'ajustement 10 lorsque la ligne prédéfinie de référence et le point de contact 12 sont situés du même côté de la ligne de détection 17, ce par quoi le matériau est freiné, au point de contact 12, par l'organe d'ajustement 10 et donc entraíné en pivotement dans l'autre sens (flèche F2 figures 7 et 8) par rapport à la plaque porte-ouvrage 4.

The control circuit 19 is of all or nothing type and is adapted to control the drive means 13, 15 according to the value of the position signal from the detector 16:

• in the directly driven state of the adjustment member 10 when the predefined reference line and the contact point 12 are on either side of the detection line 17, whereby the material is accelerated to contact point 12 by the adjustment member 10, and therefore is pivotally driven in one direction (arrow F1 Figures 5 and 6) relative to the book holder plate 4,
• in the braked state of the adjustment member 10 when the predefined reference line and the contact point 12 are located on the same side of the detection line 17, whereby the material is braked, at the contact point 12 , by the adjustment member 10 and therefore driven in pivoting in the other direction (arrow F2 Figures 7 and 8) relative to the book holder plate 4.

In the embodiment shown and according to the invention, when the plate 16b of the detector 16 is covered with material, the sphere 10 is driven in forward rotation, which tends to accelerate the material (Figure 5). On the contrary, when the plate 16b is discovered (Figure 7), the control circuit 19 places the motor 15 in the braked state, which tends to brake the material at the point of contact 12 and rotate it in the direction of overlap of the plate 16b. As and when measurement of the seam, the position signal changes very quickly state, since the edge of the material is always at least substantially in line with the plate 16b. The sphere 10 is therefore requested at high frequency in the state driven in the forward direction and in the braked state alternately. This frequency of change of state can reach a high value, especially greater than 10 Hertz.

The adjustment member 10 is mounted so that the contact point 12 is offset laterally from the drive right 18, and so that, in operation, its peripheral speed V1 at the point of contact 12 maintains a fixed orientation. More general, the plane perpendicular to the work-holding plate 4 which contains the direction of the peripheral speed V1 at contact point 12, form with a perpendicular plane to the work-holding plate 4 and parallel to the right drive 18, a fixed angle of orientation α (Figure 4) non-zero less than 90 °. This fixed angle α is also the angle formed by the axis XX 'with respect to the line 20 perpendicular to the drive line 18. According to the invention, this orientation angle α is not zero, of so that the sphere 10 tends to extend the piece laterally of material in the directly driven state. according to the invention, this orientation angle α is advantageously greater than 20 ° and less than 45 °. For example, it is around 40 °.

The part 8 associated with the frame 3 of the machine and carrying the jack 7 is provided with adjustment means prior to the angle of orientation α, i.e. it is mounted so that it can be rotated around a vertical axis with respect to the machine frame. However, in operation, this orientation angle α remains fixed and the part 8 is locked in position by everything appropriate means. As a variant, these adjustment means can be provided between the support bracket 9 and the cylinder rod 7.

Furthermore, according to the invention, the organ 10 is mounted so that the contact point 12 is located, in operation, at least substantially at right of the presser foot 5. In other words, a plan perpendicular to the work plate 4 and to the right 18 and which contains the contact point 12, goes through the presser foot 5.

More specifically, the organ 10 is mounted so that a plane perpendicular to the work-holding plate 4 which contains a straight line passing through the point of contact 12 and through the inlet 21 of the presser foot 5 forms an angle β of the order 90 ° with a plane perpendicular to the work plate 4 which contains the drive line 18 (figure 4).

If the angle β is significantly less than 90 °, the effectiveness of the guidance device in the braked state is reduced or even canceled. Indeed, the presser foot 5 very quickly tends to exert incompatible traction with the braking of the material at the point of contact 12. From even, if the angle β is significantly greater than 90 °, and in particular from around 100 °, the guidance is no longer effective in the driven state direct since the material acceleration intervenes downstream of the presser foot 5, at a point which does not allow the part to pivot.

So unlike the state of the previous technique where we tried to guide and adjust the transverse position of the piece of material immediately upstream of presser foot 5 and in a zone at least appreciably located in the axis of the right drive, the guide device according to the invention is placed at least substantially to the right of entrance 21 of the presser foot 5 and reaches its maximum efficiency for this position. In this way, it is possible to realize both concave seams (Figures 5 and 6) and convex (Figures 7 and 8) with great efficiency and great guidance precision.

The device according to the invention comprises advantageously means 28, 29, 30 for adjusting the position of the contact point 12 relative to the presser foot, and in particular adjustment means 28, 29, 30 said angle β. For example, the part 8 carrying the cylinder 7 vertical and the support bracket 9, can be mounted by compared to the frame 3 of the machine via a horizontal slide system 29 integral with the part 8 and with a threaded rod 28 fixed on this frame 3, the position of the part 8 along the rod 28 can be adjusted by example by nuts 30 (one on each side of the part 8 to block it).

The slides 29 and the rod 28 extend parallel to the direction of drive of the material by the presser foot 5, so that these means 28, 29, 30 adjust the position of the contact point 12 parallel to this direction.

In addition, in the case of parts whose cut does not allow to reach from the start of sewing the point of contact 12 with the adjustment member 10 in position to the right of the presser foot, the device according to the invention includes means (not shown) for move support piece 8 upstream before start sewing and presser foot training so that the adjustment member 10 comes into contact with the tissue. These means are also suitable for moving again downstream support piece 8, simultaneously with start of sewing, with a speed slightly lower than the drive speed V2 by the presser foot until the adjusting member 10 returns to its normal position substantially to the right of the presser foot. These displacements can be obtained simply thanks to a horizontal double acting pneumatic cylinder (not shown) mounted on the frame to move the support piece 8 horizontally and at least substantially parallel to the direction of training.

The control circuit 19 includes a electronic control circuit 22 in all or nothing which receives the position signal delivered by the detector 16, analyze this signal to determine if it corresponds to a presence or absence of material (by comparing the analog electrical signal received at a threshold), and elaborates a two-state signal corresponding respectively to the direct drive state and braked state of the adjustment member 10. Thus, this electronic circuit of piloting 22 delivers either a drive signal in direction direct from the motor 15 able to place the adjustment member 10 in the directly driven state, a signal of braking of the motor 15 able to place the adjustment member 10 in braked state, depending on the state of the position signal delivered by the detector 16.

The signal delivered by the control 22 is supplied to a motor control card 23 15 step by step. This control card 23 develops and supplies to the motor 15 an electrical supply (in the form frequency pulses proportional to the speed of rotation sought) corresponding to the state determined by the control circuit 22, in which the member 10 should be placed.

According to a variant of the invention, the control circuit 19 receives a signal representative of the value of the speed V2 of entrainment of the material by the presser foot 5, and the control board 23 is adapted to deliver a direct drive signal such as that the value of the peripheral speed V1 of the organ adjustment 10 is in constant relation with the drive speed V2. In this way, we can ensure that V1 '> V2' whatever the value of V2, which can possibly be adjustable and vary.

Advantageously and according to the invention, especially in the case of borders of pieces, the major part has a small curvature, we choose this ratio constant so that V1 'is little more than V2' (V1 little greater than V2 ").

Such control logic in all or nothing is extremely simple to achieve. For example, the direct drive signal corresponds to a driving the motor 15 at maximum speed in the direct direction, and the braking signal corresponds to a stop signal from the motor 15.

As a variant or in combination, the means of the adjustment member 10 can include means for clutching / disengaging the member adjustment 10 with respect to a motor movement. So, you can use the main motor of the sewing machine to drive the adjustment member 10 and provide a clutch / brake device in the kinematics of transmission. For example, a clutch / brake control electric can be provided on the rotary shaft 14 bearing the roller 13, this clutch / brake device receiving the motor movement on one side and transmitting it or not to the shaft carrying the roller 13 on the other side.

According to another variant, it is also possible to drive roller 13 at constant speed nominal and move the adjuster 10 by relative to the driven roller, either in a position where it is engaged in contact with the roller 13, either in a position where it is moved away from the roller 13 and disengaged. AT the disengaged state, the adjustment member 10 can also be applied on contact with a fixed part to brake it. For example, the tree 11 which carries the sphere 10 can be mounted at the end of the actuating rod of a jack horizontal carried by the support bracket 9.

Also, it is advantageous to be able to drive the adjustment member 10 in a retrograde direction reverse in the direct sense, in particular to carry out convex angle seams (Figure 8). The circuit of command 19 is then adapted to be able to place the member adjustment 10 in a state, said state of training in retrograde direction, where it is entrained in retrograde direction by the means 13, 15 of training.

• état simplement débrayé du mouvement moteur qui entraíne en sens direct (variante non représentée à embrayage/débrayage),
• état bloqué en rotation et arrêté,
• état entraíné en sens rétrograde.

Thus, according to the invention, the braked state of the adjustment member 10 includes in particular the following states:

• state simply disengaged from the motor movement which drives in the direct direction (variant not shown with clutch / disengage),
• state blocked in rotation and stopped,
• state driven in retrograde sense.

The roller 13 and the adjusting member 10 are adapted to have as low an inertia as possible, including enough rotational inertia weak so as not to drive the motor 15 by inertia forward rotation when a stop signal or backward rotation, or more generally a signal to change direction of rotation, is applied to motor 15. It is indeed necessary to prevent the motor 15, especially in the case of a stepping motor, does not lose its reference in rotation due to the inertia in rotation of the roller 13 and / or sphere 10. Advantageously, the roller 13 is made of light alloy, especially of alloy aluminum and / or with lights and recesses for lighten.

The guide device also includes means 26 for blowing the material upstream of the presser foot 5, arranged so as to be able to apply a air flow on the antagonistic effect material to the entrainment of the material induced by the adjustment member 10 in the directly driven state. So, we represented in FIGS. 1 and 2 a nozzle 26 for blowing air tablet which opens immediately upstream of the presser foot 5 and blows an air current upstream and into a direction substantially parallel to that of speed V1 (angle α with respect to the direction of drive) for spread the material before entering the presser foot 5. This draft tends to unwind the edge of the material, place it on plate 4, and extend the portion of material upstream of the presser foot in the opposite direction to one in which the material is entrained by the sphere 10 at contact point 12. This avoids all rubbing and any puckering that could harm the reliability of edge detection by the detector 16. Also a blowing nozzle 31 is provided for open out between the shafts 11, 14 carrying the roller 13 and sphere 10, so as to extend the material immediately downstream of the point of contact 12 in the direction of the peripheral speed V1 of training by the sphere 10. We avoids jams and wrinkles each time rotation of the sphere 10 in the direct direction.

In addition, a suction mouth lateral 27 is arranged on the side of the entrance 21 of the presser foot, opposite the adjusting member 10. This mouth 27 is located on the side of the wafer. detection 16b, and allows to press the edge of the material on this plate 16b avoiding creases. If necessary (variant not shown), a guide, for example in the form caliper with opening oriented laterally towards the plate 16b, can be provided immediately on the side of the plate 16b to improve the precision of the guidance of the edge of the material opposite the plate 16b.

The minimum radius of curvature can be carried out automatically by the guide device the invention depends on the difference between the speed V1 direct drive device of the sphere 10 and the drive speed V2 of the presser foot 5 as explained above, as well as the distance between the contact point 12 and the presser foot 5. Nevertheless, it is possible to achieve concave radii of curvature as small as possible, even concave angles in decreasing the speed V2 of driving by the presser foot 5, or even by stopping this training. To do this, we don't does not depend on the value of the speed V1 of the sphere 10 of that of the speed V2 drive.

In the embodiment shown on Figure 5, the device has a second detector 24 optical, similar to detector 16, which is located the opposite of the detection line 17 with respect to the organ adjustment 10. This second detector 24 has the function detect the presence of the edge of the piece of material P in the case of concave curves with extremely curvature pronounced or angular. If this detector 24 is covered with material it transmits a signal corresponding to a circuit of the V2 presser foot speed control 5, and this control circuit decreases or cancels the speed V2. So if the peripheral speed V1 direct drive is not enough to rotate the piece of material P of sufficient amplitude in the direction of arrow F1 to discover the plate 16b (figure 6), the edge of the piece of material will come cover the second detector 24, which has the effect of command stop or decrease speed V2 presser foot 5. Therefore, the pivoting can be fully effective until this second detector 24 is again discovered. this is particularly advantageous for room borders concaves with acute angles.

As a variant or in combination, the state directly driven includes not only a state driven in a direct direction at a nominal speed V1 little more than V2 "(or V1 'little more than V2'), but also a state driven in direct direction at high speed at a speed V1 much higher than V2 ", for example from the order of double or triple V2 ". So, alternatively or in combination with stopping or decreasing the speed V2, the adjustment member 10 can be controlled at the state driven in a direct direction at high speed when the second detector 24 is covered. this is particularly advantageous in the case of borders of concave parts with obtuse angles. To do this, just provide the stepper motor 15 with frequency signals greater, for example, double or triple the frequency controlling the nominal speed. So in the state driven in the forward direction, the value of speed V1 device is not always the same, and may vary between various values. The same applies to the relationship between the value of the peripheral speed V1 of the organ adjustment 10 and that of the drive speed V2.

The same arrangement can be provided in the direction of the convex curves. We have for example represented in FIG. 8 a third detector 25 which, when discovered, transmits a signal to the V2 speed control which stops or brakes the presser foot 5 drive, so that the piece of material can be rotated in the direction of arrow F2 by retrograde direction of the sphere 10 until its edge comes to cover again this third detector 25. It is easy to understand that the radius of curvature of the convex curves obtainable automatically can be extremely weak or even angular thanks in particular to such a detector 25.

In addition, by driving the sphere 10 into retrograde direction, the radii of curvature are further reduced can be performed without changing the speed presser foot drive 5.

Figures 5 to 8 illustrate different examples of automatic stitching that can be made on a machine according to the invention, as well as different states of the adjustment member 10.

In FIG. 5, a seam is made on along a concave edge of strong curvature of the piece P in sewing piece E which is for example a neckline round. In the state shown, the plate 16b is covered and the point I of intersection between the edge of the material and a straight line that goes through the detection zone 16b and which is perpendicular to the detection line, is on the side opposite the point of contact 12 with respect to the detection line 17. The adjustment member 10 is then driven in the direct direction at the peripheral speed V1. The second detector 24 is not covered, so that the presser foot is driven at its normal speed V2, inducing a speed V2 'of the material at the point of contact 12 (if β = 90 °, and if the training is done normally V2 = V2 '), of which the component V2 "in the direction of V1 is such that V1> V2 ". The peripheral speed V1 of the adjustment member 10 has a component V1 'according to the direction of training which is oriented downstream, that is to say in the same direction as speed V2 presser foot 5. Workpiece P tends to rotate according to arrow F1 until the plate 16b is discovered, after which the adjustment member 10 will be placed in the braked state, for example by stopping the engine 15.

In FIG. 7, a seam is made on along a convex edge. In the state shown, the plate 16b is discovered, and said point I intersection is on the same side of the detection line 17 as the contact point 12, the adjustment member 10 being in the braked state with V1 = 0. The presser foot 5 drives the material at speed V2, which induces pivoting according to the arrow F2 tending to cover the wafer 16b.

In the example of Figure 6, we realize sewing along a concave angle (for example a collar in V). The edge of the material covering the second detector 24, the drive by the presser foot 5 is interrupted (V2 = 0). The plate 16b being covered, the adjusting member 10 is in the driven state direct at speed V1, which induces pivoting according to arrow F1. As soon as the detector 24 is discovered, the presser foot drive at speed V2 will be reactivated. In a variant not shown, the second detector 24 can be replaced by several detectors, separate, for example a detector for stopping training and another for his recovery.

In the example of figure 8, we realize a seam along a convex angle. The third detector 25 being discovered, the drive by the presser foot 5 is interrupted, and the adjusting member 10 is driven backward at speed -V1 to improve the efficiency of pivoting according to arrow F2.

The invention makes it possible in particular to perform high-speed automatic stitching with a high sewing precision and with radii of curvature any, especially very weak. She is in particular applicable to the automatic installation of parts E neckline and allows the realization of V-necks or collar with small radius of curvature.

The invention can be the subject of various variations from the embodiments described and represented. In particular, the adjustment member arranged to the right of the presser foot can be realized in the form a circular wheel, an endless belt ... and come to contact of the material at several points of contact, or even according to a surface contact zone (which is offset laterally and at least substantially in line with the presser foot). Also, several adjustment bodies can be provided (for example one in the direct direction, one in retrograde direction, or one on each side of the presser foot and from the right of drive 18 ...). Also, the invention is applicable to a left head sewing machine or head right.

The invention is also applicable with other embodiments of the drive means and control means of the adjustment member.

Claims (23)

1. Device for guiding flexible textile material (fabric, knitwear, etc) which can be sewn, fitted onto a sewing machine which is provided with a work-holder plate (4), and with a presser foot (5) for entrainment of the material in a longitudinal direction of entrainment, which is associated with at least one needle (6), in order to permit execution of automatic sewing of the material, this device for guiding comprising:

   at least one unit (10) for adjustment of the transverse position of the material, which is fitted such as to rotate and come into contact with the material, and is designed to be able to modify the speed of entrainment of the material locally, when it is applied to the material;

   means (7) for application of the unit (10) for adjustment, continually in contact with the material, at a point of contact (12) which is offset laterally by a straight line (18), known as the entrainment line, which passes via the presser foot (5), and is parallel to the longitudinal direction of entrainment;

   characterised in that the means (7) for application are designed, and the unit (10) for adjustment is fitted such that:

   in operation, the said point of contact (12) is located at least substantially on a line perpendicular to the presser foot (5) ;

   in operation, a plane which is perpendicular to the work-holder plate (4) at the point of contact (12), and contains the direction of the peripheral velocity (V1) of the unit for adjustment, at the point of contact (12), forms with a plane which is perpendicular to the work-holder plate at the point of contact, and is parallel to the said entrainment line (18), a fixed orientation angle (α) which is not zero.
2. Device according to claim 1, characterised in that the orientation angle (α) is less than 90°.
3. Device according to claim 1 or claim 2, characterised in that the orientation angle (α) is between 20° and 45°.
4. Device according to any one of claims 1 to 3, characterised in that it comprises means for prior adjustment of the orientation angle (α).
5. Device according to any one of claims 1 to 4, characterised in that the unit (10) for adjustment is fitted such that a plane which is perpendicular to the work-holder plate (4), which contains a straight line (20) which passes via the said point of contact (12) and via the intake (21) of the presser foot (5), forms an angle (β), of approximately 90°, with a planewhich is perpendicular to the work-holder plate which contains the entrainment line (18).
6. Device according to any one of claims 1 to 5, for execution of automatic sewing of the material parallel to a pre-defined reference line, comprising:

   means (13, 15) for rotation, by drive movement generated by a motor (15), of the unit (10) for adjustment, in at least one direction, known as the direct direction, for which the peripheral speed (V1) of the unit (10) for adjustment, at the point of contact (12), has a component (V1') in the direction of entrainment, which is oriented in the direction of entrainment of the material by the presser foot (5);

   a detector (16) for the transverse position of the said pre-defined reference line, which is fitted upstream from the presser foot (5), and is associated with means for generation of a position signal, the value of which varies according to whether the said pre-defined reference line is on one side or the other of a straight line (17), known as the detection line, which passes via the detector (16), and is parallel to the entrainment line (18),

   the said device being characterised:

   in that the means (13, 15) for entrainment are designed to be able to entrain the unit (10) for adjustment in a direct direction, at a peripheral speed (V1) of the unit (10) for adjustment, at the point of contact (12), which is greater than the component (V2"), at the point of contact (12), and according to the direction of the said peripheral velocity (V1), of the speed (V2) of entrainment of the material by the presser foot (5);

   in that the means (13, 15) for entrainment of the unit (10) for adjustment are designed to put and keep the unit (10) for adjustment in one of the following states: a state, known as the entrained state, in the direct direction, in which it is entrained, at the said peripheral speed (VI), in the direct direction, by the means (13, 15) for entrainment; and a state, known as the braked state, in which the said peripheral speed (V1) is lesser than, or is in the direction opposite to, the said component (V2") of the speed (V2) of entrainment of the material by the presser foot (5);

   and in that it comprises means (19) for control, of the all-or-nothing type, which are designed to control the means (13, 15) for entrainment, according to the value of the said position signal:

   in the entrained state, in the direct direction, of the unit (10) for adjustment, when the said point of contact (12) and the said pre-defined reference line are on both sides of the detection line (17), such that the material is accelerated, at the point of contact (12), by the unit (10) for adjustment, and is thus pivoted in one direction (F1) relative to the work-holder plate (4); and

   in the braked state of the unit (10) for adjustment, when the said point of contact (12) and the said pre-defined reference line are located on the same side of the detection line (17), such that the material is braked, at the said point of contact (12), by the unit (10) for adjustment, and is thus pivoted in the other direction (F2), relative to the work-holder plate (4).
7. Device according to claim 6, characterised in that it comprises means for braking the unit (10) for adjustment, which are designed to lock the unit (10) for adjustment in the braked state.
8. Device according to claim 6 or claim 7, characterised in that the means (13, 15) for entrainment are designed to be able to entrain the unit (10) for adjustment in a rearward direction, which is the inverse of the direct direction.
9. Device according to any one of claims 6 to 8, characterised in that the means (13, 15) for entrainment comprise an entrainment motor (15), and in that the said means (19) for control comprise an all-or-nothing electronic piloting circuit (22), which can provide either a signal for entrainment, in the direct direction of the motor (15), corresponding to the entrained state, in the direct direction, of the unit (10) for adjustment, or a signal for braking of the motor (15), corresponding to the braked state of the unit (10) for adjustment, according to the state of the said position signal.
10. Device according to any one of claims 6 to 9, characterised in that the unit (10) for adjustment is of the rotary type, and is fitted such as to rotate freely around an axis (XX'), and in that the means (13, 15) for entrainment comprise a drive unit (13), which can be connected in rotation to the unit (10) for adjustment, at least in the driven state, in the direct direction, and means for rotating this drive unit, in the direct direction, on the basis of a drive movement, at a speed of rotation which corresponds to the said peripheral speed (V1) of the unit (10) for adjustment.
11. Device according to claim 10, characterised in that the drive unit (13) is a roller, which is fitted such as to rotate around an axis (ZZ'), so as to be able to be supported against the unit (10) for adjustment, in order to rotate the latter by friction contact.
12. Device according to claim 9 and claim 11, characterised in that the roller (13) is connected in rotation to the said motor (15), and in that the roller (13) and the unit (10) for adjustment are designed to have inertia in rotation which is low enough not to rotate the motor (15), in the direct direction, when a signal for stoppage or a change of direction of rotation is applied to the motor (15).
13. Device according to claim 12, characterised in that the roller (13) is made of light alloy, and in particular of aluminium alloy.
14. Device according to any one of claims 1 to 13, which permits execution of automatic sewing of a piece of material along one of its edges, which constitutes the said pre-defined reference line, characterised in that:

    the position detector (16) is a detector for the presence or absence of material, associated with means for generation of a position signal with two states, which are representative of the presence or absence of material; and

    the control means (19) are designed to control the means (13, 15) for entrainment, alternately from the entrained state, in the direct direction, to the braked state, or the contrary, depending on the state, and at each change of state of the position signal.
15. Device according to any one of claims 1 to 14, characterised in that it comprises means (26) for blowing material upstream from the presser foot (5), which are disposed such as to be able to apply a current of air onto the material, with an effect which opposes the entrainment of the material induced by the unit (10) for adjustment, in the entrained state, in the direct direction.
16. Sewing machine, characterised in that it comprises at least one guiding device according to any one of claims 1 to 15.
17. Method for automatic sewing of a piece of flexible textile material (fabric, knitwear, etc) by means of a sewing machine, wherein there is continual application of at least one unit (10) for adjustment, which is rotary in contact with the material, at at least one point of contact (12) on the material, which is offset laterally from the entrainment line (18), characterised in that the unit (10) for adjustment is applied at at least one point of contact (12), which, in operation, is located at least substantially at the level of the presser foot (5), and in that the unit (10) for adjustment is fitted, applied, and kept continually applied in contact with the material, such that, in operation, a plane which is perpendicular to the work-holder plate (4) at the point of contact (12), and contains the direction of the peripheral velocity (V1) of the unit for adjustment at the point of contact (12), forms a fixed orientation angle (α), which is not zero, with a plane which is perpendicular to the work-holder plate, at the point of contact, and parallel to the said entrainment line (18).
18. Method according to claim 17, characterised in that the orientation angle (α) is less than 90°.
19. Method according to claim 17 or claim 18, characterised in that the orientation angle (α) is between 20° and 45°.
20. Method according to any one of claims 17 to 19, characterised in that the unit (10) for adjustment is applied at a point of contact (12), which is located such that a plane which is perpendicular to the work-holder plate, which contains a straight line (20) which passes via the said point of contact (12) and via the intake (21) of the presser foot (5) , forms an angle (β), of approximately 90°, with a plane which is perpendicular to the work-holder plate which contains the entrainment line (18).
21. Method according to any one of claims 17 to 20, wherein there is detection of the transverse position of a pre-defined reference line of the material, in a detection area (16b) upstream from the presser foot (5), and a position signal is generated, the value of which varies according to whether the said pre-defined reference line is on one side or the other of a straight line, known as the detection line (17), which passes via the detection area (16b) and parallel to the entrainment line (18),
    characterised in that:

    the unit (10) for adjustment is placed, and kept, in one of the two following states, according to the value of the position signal: a state of rotation, in the direct direction; and a braked state:

    in the entrained state, in the direct direction, the unit (10) for adjustment is entrained at a speed which corresponds to a peripheral speed (V1) of the unit (10) for adjustment, at the point of contact (12), which is greater than the component (V2"), at the point of contact (12), and according to the direction of the said peripheral velocity (V1), of the entrainment speed (V2) of the material by the presser foot (5);

    in the braked state, the entrainment of the unit (10) for adjustment is controlled such that the said peripheral speed (V1) is lesser than, or is in the direction opposite to, the said component (V2") of the speed (V2) of entrainment of the material by the presser foot (5) ;

    the unit (10) for adjustment is put and kept in the state in which it is rotated, in the direct direction, when the said point of contact (12) and the said pre-defined reference line are on both sides of a straight line (17), known as the detection line, which passes via the detector (16), and parallel to the entrainment line (18), such that the material is accelerated, at the said point of contact (12), by the unit (10) for adjustment, and is thus pivoted in one direction (F1) relative to the work-holder plate (4); and

    the unit (10) for adjustment is put and kept in the braked state, when the said point of contact (12) and the said pre-defined reference line are located on the same side of the detection line (17), such that the material is braked, at the said point of contact (12), by the unit (10) for adjustment, and is thus pivoted in the other direction (F2), relative to the work-holder plate (4).
22. Method according to claim 21, characterised in that the unit (10) for adjustment is locked, in order to stop it in the braked state.
23. Method according to claim 21 or claim 22, for execution of automatic sewing of a piece of material along one of its edges, which constitutes the said pre-defined reference line, characterised in that:

    the presence or absence of material is detected in at least one detection area (16b), which is situated upstream from the presser foot (5), on the planned path of the edge to be detected;

    there is generation of a position signal with two states, which are representative of the presence or absence of material; and

    the change of state of the unit (10) for adjustment is controlled, alternately from the entrained state, in the direct direction, to the braked state, or the contrary, depending on the state, and at each change of state of the position signal.

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