EP0232291B1 - Computer-controlled electric sewing machine - Google Patents

Abstract

The present computer-controlled electric sewing machine wherein the rotational speed of the central drive motor (M) is servo-controlled by means of a regulating circuit (O, CL, Cs) including a tachymetric control generator (G) has a mechanism for driving a support of a cop (C) to be reeled, comprising the assembly of structural elements of the generator (G), a double-acting clutch device (EA) enabling mechanical connection of the rotor of the generator (G) either to the central motor (M) or to the cop support, electric switch means (IE, IG) providing for in the latter case the connection of the armature of the generator (G) to an electric supply source (A) while preventing current from being supplied to the central control motor (M) of the machine.

Description

The present invention relates to an electric sewing machine, with computerized control, and more particularly to a machine in which the speed of rotation of at least certain mobiles is dependent on the action of an electronic regulator, the detection circuit of which includes at least one tachometric generator kinematically integral with said mobiles, intended to deliver a voltage representative of their instantaneous speed of rotation, and at least one reference voltage source, of value, varying with the position occupied, at each instant, by an actuator of the machine, this regulator acting on the speed of rotation of the mobiles by permanent comparison of said voltages.

Many sewing machines of this type are already known, generally belonging to two distinct classes, namely those in which said mobiles are capable of being mechanically attached by the regulator, either to a drive motor rotating at substantially constant speed, or to a braking device, depending on whether the signal delivered by the generator deviates in one direction or the other with respect to the value of the reference voltage, and those in which the mobiles in question are always kinematically integral with the engine machine drive, the regulator acting on the current supply to the motor in order to vary the speed of rotation in reverse to the deviations noted by the generator from the set value fixed by the position occupied by the machine actuator.

The state of the art concerned by the first of these two classes of electric sewing machine includes in particular the Swiss patents 635 382 and the United States of America 4 377 778 as well as the European patent applications published under the numbers 67 072 , 67 649 and 104 913.

The second class of electric sewing machines mentioned above is illustrated, for example, by Soviet patent 529,273 and, more recently, by Japanese Kokai 57-25187.

As in the case of machines with purely mechanical, even electro-mechanical functioning, the known electric sewing machines, with computerized control, all include, as an essential accessory, a device intended to allow the user to wind thread on an empty can and having, on the one hand, a rotary support on which the can is removably fixed and, on the other hand, a motor mechanism for driving this support in rotation.

Such a device can take different forms and, in particular, as shown, for example, by the patents of the United States of America 3,587,494, 4,091,755 or 4,161,153 as well as the French patent 2,078 167, it can include a whole clutch system which should allow the user to connect, momentarily and kinematically, the can holder to the electric motor driving the entire machine, either directly or to a driven intermediate mobile by this one.

It has also been proposed to make use of an auxiliary motor of low power, having use only that of direct drive of the can holder and which the user can put, at will, in service or out of service ( U.S. Patent Nos. 2,255,152 and 3,741,492, published German application 3,501,638 AI and French patent 2,187,185.

The drawbacks of one or the other of these two solutions are well known to those skilled in the art: in fact, while the adoption of a computerized control should, in principle, make it possible to significantly reduce the number and architecture of the parts driven by the machine motor, the amplitude of the needle throw and fabric transport movements being imposed "in situ" by individual stepper motors, controlled by the control computerization of the machine, and thus lead to a structural simplification and, as a corollary, to a reduction in the risks of mechanical breakdowns and in manufacturing and maintenance costs which, in principle, must also result in a reduction in the dimensions of the housing of the machine and therefore also its weight, the forced adoption of one or other type of winding device and its inclusion, as a "foreign body" among the structural elements used exclusively for the function "coutur e "lessen the impact that one would be entitled to expect from the adoption of a technical solution as sophisticated as that implemented in a sewing machine with computerized control, that is to say in which its various functions are controlled by a microprocessor from coded instructions and stored in a "solid state" type read-only memory, in particular a ROM or a PROM.

• a) l'ensemble des organes constituant la génératrice tachymétrique,
• b) un embrayage à double action permettant d'accoupler mécaniquement le rotor de la génératrice soit aux mobiles rotatifs de la machine, dans une première position de travail, soit au support de cannette, dans une seconde position de l'embrayage,
• c) des moyens de commutation associés à cet embrayage permettant de brancher l'induit de la génératrice à une source de tension d'alimentation en vue d'assurer l'entraînement électromagnétique du rotor, lorsque l'embrayage occupe sa seconde position de travail, et d'interrompre ce branchement dans la première position de travail de l'embrayage,
• d) et, enfin, des moyens interrompant l'entraînement desdits mobiles pendant le bobinage de la cannette.

The present invention, which specifically relates to an electric sewing machine, with computerized control, of the type defined above and including, like known machines, a bobbin winding device comprising, as described, a bobbin holder and a motor mechanism for the rotational drive of such a support, aims to obviate the above drawbacks and proposes, for this purpose, that this mechanism includes

• a) all the organs constituting the tachometric generator,
• b) a double-action clutch enabling the rotor of the generator to be mechanically coupled either to the rotary mobiles of the machine, in a first working position, or to the can holder, in a second position of the clutch,
• c) switching means associated with this clutch making it possible to connect the armature of the generator to a supply voltage source in order to ensure the electromagnetic drive of the rotor, when the clutch occupies its second position work, and to interrupt this connection in the first working position of the clutch,
• d) and, finally, means interrupting the driving of said mobiles during the winding of the can.

In a particular embodiment of the present invention, the switching means are arranged so as to allow the armature of the generator to be connected either to the electronic regulator detection circuit, in the first working position of the clutch, either at said power source, in the second working position thereof.

The invention therefore finds an interesting application both in electric sewing machines coming from the first of the two classes of machines mentioned above and from the second class.

In the latter case, that is to say in that of an electric sewing machine, with computerized control, in which said rotary mobiles are permanently, mechanically, integral with a central motor driving the machine, the electronic regulator then acting directly on the speed of rotation of this motor, this sewing machine is characterized by prior machines, advantageously and moreover, by the fact that the means for interrupting the driving of the mobiles are constituted by a circuit switch acting on the current supply to the motor, this circuit being associated with the clutch so as to prohibit this supply as long as this clutch occupies its second working position.

• - la fig. 1 est une vue en élévation, de trois quarts, de la machine à coudre selon l'invention;
• - la fig. 2 est une vue de détail de la machine en perspective plongeante et à très grande échelle, montrant le support de cannette et une partie des éléments de l'embrayage à double action dont est muni le mécanisme-moteur, d'entraînement, de ce support;
• - la fig. 3 est une vue de dessous, en perspective et avec arrachement, de la partie de la machine voisine de l'encastrement du bras supérieur de celle-ci avec la portion verticale du boîtier, montrant d'autres organes de ce mécanisme-moteur;
• - la fig. 4 est une vue en perspective, de dessous, du mécanisme d'entraînement du support de cannette;
• - la fig. 5 est une vue éclatée, de détail, illustrant les cinématismes essentiels de ce mécanisme-moteur;
• - les figs 6 et 7 sont des vues schématiques, dans deux positions distinctes de certains éléments, illustrant le fonctionnement de l'embrayage à double action dont est muni le mécanisme d'entraînement du support de cannette;
• - la fig. 8 est une coupe méridienne selon VIII - VIII de la fig. 5 et la fig. 9 une coupe transversale selon IX - IX de la fig. 8;
• - la fig. 10 représente le schéma de principe du circuit de commande de la machine à coudre électrique, selon une première forme d'exécution de l'invention;
• - la fig. 11 montre quatre diagrammes explicatifs du fonctionnement du régulateur électronique dont est équipée la machine.
• - la fig. 12 représente un schéma similaire à celui de la fig. 10 selon une seconde forme d'exécution de l'invention.

Other interesting characteristics and particularities of the electric sewing machine, with computerized control, in accordance with the present invention will now be described with reference to the appended drawings, given by way of example, in which:

• - fig. 1 is an elevational view, three quarters of the sewing machine according to the invention;
• - fig. 2 is a detail view of the machine in plunging perspective and on a very large scale, showing the can holder and part of the elements of the double-action clutch with which the motor-drive mechanism is provided. ;
• - fig. 3 is a bottom view, in perspective and with parts cut away, of the part of the machine adjacent to the embedding of the upper arm thereof with the vertical portion of the housing, showing other members of this motor mechanism;
• - fig. 4 is a perspective view, from below, of the drive mechanism of the can holder;
• - fig. 5 is an exploded view, in detail, illustrating the essential kinematisms of this motor mechanism;
• - Figs 6 and 7 are schematic views, in two separate positions of certain elements, illustrating the operation of the dual-action clutch with which the drive mechanism of the can holder is provided;
• - fig. 8 is a meridian section along VIII - VIII of FIG. 5 and fig. 9 a cross section along IX - IX of FIG. 8;
• - fig. 10 shows the block diagram of the control circuit of the electric sewing machine, according to a first embodiment of the invention;
• - fig. 11 shows four explanatory diagrams of the operation of the electronic regulator with which the machine is equipped.
• - fig. 12 shows a diagram similar to that of FIG. 10 according to a second embodiment of the invention.

The sewing machine visible in fig. 1 is an electric machine, with computerized control, that is to say a machine in which the essential functions are controlled and managed electronically by a microprocessor from detailed instructions, stored beforehand in one or more memories, preferably "solid state" memories, random access. These instructions may, for example, consist in the choice of sewing speeds according to the nature and / or the thickness of the pieces to be sewn, the type of stitch to be executed, etc. In this succinct representation of the machine , essentially noted both switches Ip and _Ib serving respectively to power up the machine after connection to the mains by an electric cord, not shown, and the commissioning and decommissioning of an electrical device allowing the user to wind a can C with wire taken from a reel, also not shown.

As for the actual operating mode of this machine, reference is made to FIG. 10 which illustrates schematically the main structural elements of the control circuit, according to a first embodiment.

In the drawing, rectangle 1 symbolizes a microprocessor and the memory associated with it, rectangle 2 represents a control block of a central motor M for driving the machine to which can be coupled, in the manner which will be described by next, a tachometer generator G, also visible in G _i in this same fig. 10. This generator G-Gi is in particular part of a circuit regulating the speed of rotation of the engine M, a circuit whose essential characteristics will now be recalled although such a circuit has been known for a long time to those skilled in the art. art (see in particular sheet D542, paragraph 3,231 and fig. 44 - pages 57 and 58, published in June 1976, in chapter 3 "Control of DC motors" of the "Electric machines" part of the so-called Collection "Engineering Techniques" developed under the direction of Mr. André Belot; see also pages 3 - 22 and 3 - 23 (Figures 3.3.15 to 3.3.17) of the August 1980 edition (reprint supplemented with previous editions published in October 1972, October 1978, October 1975 and July 1978) of the publication " DC Motors Speed Controls Servos Systems "from the company called" Electro-Craft Corporation "in Hopkins, Minnesota 55343 (USA); see the explanations given on page 53, under the title "Switchmode Regulator Control Circuits" in Motorola Inc. publication 1984-F105 called "The Switchmode Guide - linear and power products").

• - Le diagramme a de la fig. 11 montre l'évolution dans le temps que peut présenter, à titre d'exemple, le signal correspondant à la valeur de consigne de la vitesse désirée;
• - Le diagramme b de cette même figure montre, dans un cas d'espèce, l'évolution dans le temps du couple de freinage appliqué à la machine;
• - Le diagramme c est caractéristique (signal C^*) de la puissance moyenne envoyée au moteur M.
• - Le diagramme d de la fig. 11 illustre le résultat de l'action du circuit de commande CS sur le courant d'alimentation du moteur M. On voit, en particulier, que ce moteur est alimenté par une suite d'impulsions de courant le de même amplitude mais dont la durée correspond à l'écart de temps pendant lequel l'amplitude du signal C^* (diagramme c) est supérieure à l'amplitude du signal impulsionnel D. Ainsi, si la vitesse du moteur M est très inférieure à la vitesse de consigne (partie de la courbe C^* comprise entre les instants t₁ et t₂), la durée des impulsions sera proportionnellement large de manière que le moteur recevra, en peu de temps, l'énergie nécessaire à en accroître la vitesse jusqu'au niveau désiré. Si, par contre, la vitesse du moteur M est plus proche que précédemment de la vitesse de consigne (partie de la courbe C^* comprise entre les instants t₂ et 1₃), les impulsions le seront par contre de durée plus réduite. Cette durée pourra croître sans variation importante de la vitesse du moteur si ce dernier est appelé à fournir un couple plus important (voir par exemple la partie extrême droite du diagramme d de la fig. 11), par exemple si la machine doit, à l'instant t₃, coudre un empilage de tissu d'épaisseur croissante. Les publications citées précédemment donnent des détails exhaustifs sur l'aspect plus particulièrement théorique du fonctionnement du circuit de régulation décrit. Elles sont citées dans la présente demande à titre de référence.

As is known, such a regulating circuit comprises, in addition to the tachymeter generator G-Gi already mentioned, an oscillator O constituting a time base, delivering a periodic sawtooth signal D (fig. 11 c) to a circuit CS command receiving, moreover, a signal C ^* emanating from a first error amplifier Ci to which two signals, one, of polarity shown negative in the drawing, emanating from the generator G and which is therefore characteristic of the effective speed of rotation of the motor M, the other, of polarity represented positive, corresponding to a target value of the desired speed for this same motor M.

• - Diagram a of fig. 11 shows the evolution over time that the signal corresponding to the setpoint value of the desired speed can present, for example;
• - Diagram b of this same figure shows, in a specific case, the evolution over time of the braking torque applied to the machine;
• - The diagram c is characteristic (signal C ^* ) of the average power sent to the motor M.
• - Diagram d of fig. 11 illustrates the result of the action of the control circuit CS on the supply current of the motor M. It can be seen, in particular, that this motor is supplied by a series of current pulses le of the same amplitude but whose duration corresponds to the time difference during which the amplitude of the signal C ^* (diagram c) is greater than the amplitude of the impulse signal D. Thus, if the motor speed M is much lower than the set speed (part of the curve C ^* lying between the times t ₁ and t ₂ ), the duration of the pulses will be proportionally wide so that the motor will receive, in a short time, the energy necessary to increase the speed to the desired level. If, on the other hand, the speed of the motor M is closer than previously to the set speed (part of the curve C ^* lying between the instants t ₂ and 1 ₃ ), the pulses will however be of shorter duration. This duration may increase without significant variation in the speed of the motor if the latter is called upon to provide greater torque (see for example the extreme right part of the diagram d in FIG. 11), for example if the machine has to 't ₃ , sew a stack of fabric of increasing thickness. The publications cited above give exhaustive details on the more particularly theoretical aspect of the operation of the described regulation circuit. They are cited in this application for reference.

As in the case of previous electric sewing machines, the value of the setpoint signal, of positive polarity, directed to the error amplifier Ci is characteristic of the instantaneous position occupied by an actuator of the machine, for example a pedal that the user can crush more or less intensely depending on the speed of rotation desired for the central motor M. In the drawing, (fig. 10) this actuator is represented by an ohmic voltage divider A connected by its output to a DS threshold detector that includes the control unit 2, intended to deliver a signal to the microprocessor 1 warning it that the user is acting on the pedal. This microprocessor then puts switches 1 ₁ , 1 ₂ and 1 ₃ in the open position (these switches are in fact output transistors of the microprocessor), so that the circuit of the current flowing in the control block 2 is looped through resistors R ₁ , Rs and Rs. One obtains, at the output of the variable resistor R ₆ , a signal of maximum amplitude directed towards the error amplifier Ci, signal which will correspond to the maximum desired speed for the motor M. By an appropriate choice of the value of the resistors R ₄ and Rs, this speed could, for example, be of the order of 1000 rpm. By choosing resistors Ri and R ₂ of appropriate value, it will be possible to limit the imposed value of the speed of rotation of the motor M for example to 800 rpm if the microprocessor 1 commands the closing of the switch 1 ₂ , in particular after reception of a corresponding instruction read in the memory. This could, for example, be the case for the execution by the machine of a particular type of stitch.

When the user releases the actuation pedal, the threshold detector DS informs the microprocessor, which then commands the closing of the switch ₁₁ , thus determining the blocking of the diode Di so that the amplitude of the signal resistor R ₆ output will be fixed exclusively by the value of resistors R ₃ , R ₄ and R ₅ . In this case, the sewing machine motor will run at minimum speed, for example of the order of 100 rpm.

In the present sewing machine, as in all known electrical machines, the current supply to the central motor M is not interrupted once the actuation pedal is released, that is to say when this motor is brought to turn at its minimum speed (100 rpm for example) only when the machine needle is completely disengaged from the fabric it was helping to sew or decorate. For this purpose, the machine has a needle position detector, represented schematically by the rectan gle DP, detector whose structural characteristics are well known to those skilled in the art and will not be repeated here in detail. Let's just say that we can advantageously make use of a structure comprising one or more discoid masks cut out from radial slits and driven in rotation by the shaft controlling the axial movement of the needle and periodically intercepting a light ray perceived by a cell photoelectric when this ray is able to simultaneously pass through a slot belonging to each disc and whose angular position will be characteristic of the fact that the needle then occupies the desired high position.

In such a case, the signal received by the microprocessor of the photoelectric cell with which the DP detector is equipped determines the closing of the switch 1 ₃ so that, the two opposite ends of the resistors R ₄ and R ₅ being grounded , the output signal of the resistor Re is zero and the motor M is no longer supplied.

To prevent the motor M from continuing to run although the actuation pedal has been released, in particular following a malfunction of one or the other member of the control unit 2 or one or more the other switch I ₁ to 1 ₃ , this motor is supplied with current through an electronic switch controlled by the microprocessor 1, inter alia from the signal received from the generator G through an amplifier Ai.

A second amplifier A ₂ , connected between the motor M and the switch I _E , on the one hand, and the microprocessor 1, on the other hand, warns the latter that the motor M absorbs an excessive current, for example at following an abnormally intense resistant force imposed on the engine; in this case, the microprocessor will control the opening of the electronic switch I _E.

A third amplifier, A ₃ , connected between the motor M and the switch I _E , on the one hand, and the control circuit CS of the supply to this motor, on the other hand, ensures that this circuit limits the value of the current passing through the motor to a maximum threshold value.

As can still be seen in the drawing (fig. 10), the user can access, as desired, different parts of the program stored in the memory associated with the microprocessor by actuation of one or the other among the ten keys Si to S ₁₀ of a keyboard not shown in detail in FIG. 1 but whose location can be that marked by the rectangle S for example.

The sewing machine according to the invention is, moreover, equipped with two stepping motors, M _j and Mt intended for controlling the throwing of the needle, for the motor M _j , and for controlling the advance of the fabric to be sewn, for the motor Mt. The rectangles A _j1 and A _J2 , respectively An and At2, represent "driver" circuits delivering to the motor Mj, respectively M _t , the impulses necessary to angularly move their armature of the quantity and in the desired direction, these circuits being controlled by the microprocessor 1 as a function of the instructions received both from the memory and from the position detector DP (synchronization of the movements of the needle and the tissue).

As indicated with reference to fig. 1, the sewing machine according to the invention also comprises, like known machines, even if they are purely mechanical, electromechanical or electronic, with computerized control or not, a device allowing the user to proceed to the winding of a can C as soon as he has activated the rocker switch I _b .

According to an essential feature of the present invention, the rotational driving of this can, with a view to its winding, is carried out by means of the tachometric generator G-Gi in the manner which will now be described.

To this end, the machine according to the invention is in particular equipped with a dual-action clutch device making it possible to mechanically connect the axis of the generator either to the engine M, when it is desired that this generator delivers to the regulation circuit. a signal characteristic of the instantaneous speed of rotation of this motor, ie to a support Sp intended to receive the bobbin to be wound, the armature of the generator then being attached to a supply voltage source so that this generator then becomes a can driving motor. In the latter case, the current supply to the motor M is prevented, for example by opening the switch I _E.

As seen in fig. 10, it is indeed possible to supply the armature of the generator G with the voltage appearing at the output of the ohmic divider of voltage A, that is to say by a variable voltage whose amplitude will be a function of the position of the actuator, in this case the same pedal used to actuate the machine, this signal being amplified at A ₄ and being directed towards the generator through an electronic switch I _G controlled by the microprocessor 1 and capable of being carried in two active positions, one for which the generator can be connected to the actuator A, as described, the other for connecting this generator to the already mentioned regulation circuit. Of course, the connection of the generator G to a supply voltage source such as the actuator A, a low power source, only makes sense if the rotor axis of this generator, which then works in engine speed, is not mechanically connected to the motor M. This is precisely what the dual-action clutch device E _A, shown diagrammatically on the left-hand side of FIG. 10 and whose structural elements illustrated in. detail in figs 2 to 9 will now be described.

The generator Gi is driven by the motor M using the assembly shown in fig. 3 in which 3 and 4 are two toothed belts driven directly by this motor, not visible in the figure but which is located in practice in the lower part of the frame of the machine (fig. 1). These belts mesh respec tively with a pinion 5 integral with a shaft 6, on which depends the control of the reciprocating movement of the machine needle, and with a crown 7, toothed externally and internally. The belt 4 is in engagement with the external toothing of the crown 7. As for its internal toothing, this is used for driving in rotation a pinion 6 fixed on the rotor axis 9 of the generator G ₁ (figs 8 and 9) by means of a unidirectional coupling comprising a cage 10 inserted by force into an axial housing 8a of the pinion 8 and intended to maintain, between the axis 9 and the wall of this housing, five needles 11 taking place in corresponding slots 12a passing through the wall of a sleeve 12 inserted in the cage 10, between the axis 9 and longitudinal clearances 10a formed equidistantly in the internal face of the cage 10. It will further be noted that the faces the sides of each slot 12a are, one, rounded according to a radius of curvature slightly greater than the radius of the section of each needle 11 and, the other, planar. In addition, the profile of the rounded face of the slots 12a presents a solution of continuity with the profile of the adjacent clearance 10a, which is also rounded in the same way.

Thanks to the arrangement described, it is possible to drive the axis 9 by the pinion 8 provided that the latter rotates anti-clockwise (fig. 5). If it is the shaft 9 which is rotated counterclockwise, the pinion 8 will not receive any drive torque and it will be possible to block it angularly without hampering the rotation of the shaft 9 by the generator (operating as a motor).

In the sewing machine shown, the unidirectional coupling which has just been described is mounted on the shaft 9 of the generator so that this shaft is driven by the pinion 8 as soon as the ring gear 7 is driven in the direction clockwise, observing FIG. 3. It will be noted, in this regard, the very large difference in the diameters chosen for the crown 7 and for the pinion 8. In fact, to obtain, at the same time, that the generator has such small dimensions as possible and that it always rotates at speeds corresponding to an operating range in which the voltage produced by the generator remains proportional to the angular speed of the shaft of this generator, it is necessary that the value of this angular speed be relatively large, even if the machine's drive motor is running at low speed, i.e. at around 100 rpm.

On its projecting portion between the pinion 8 and the generator G _i , the shaft 9 carries a second pinion 13, angularly blocked on this shaft and engaged with a toothed plate 14 (figs 4, 5 and 10) to which is fixed a bevel gear 15 of diameter smaller than that of the plate 14. The latter is provided with a pin 14a pivotally mounted in a support 14b secured to a frame 16 (fig. 2) to which is also fixed the generator Gi (fig. 3). As seen in fig. 1, the upper part of the frame 16 (fig. 2) is flush with the surface of the upper arm of the sewing machine.

The can holder Sp (figs 2 and 5 to 7) already mentioned, is integral with one end of an axis 17 passing through a boss 16a of the frame 16 (fig. 2), perpendicular to the axis 14a of the plate 14 and pivoted, at its other end, in an ear 16b of this frame (figs 4, 6 and 7). On its portion between the boss 16a and the ear 16b, the axis 17 carries, on the one hand, a bevel gear 18 which is mounted on this axis so as to be able to slide longitudinally thereon while being integral with it angularly and, on the other hand, a spring 19, stretched between the boss 16a and the pinion 18 and pushing the latter in the direction of the ear 16b of the frame 16. The distance separating the axis 17 and the plate 14 is such that, under the action of the spring 19, the pinion 18 meshes with the pinion 15 secured to this plate. Therefore, as long as the pinion 18 remains in engagement with the pinion 15, that is to say as long as nothing moves it away from the pinion 18 by sliding on the axis 17 against the spring 19, any rotation of the axis 9 of the generator G ₁ will lead to a corresponding rotation of the axis 17 and therefore of the can holder Sp.

For obvious reasons, it is however necessary that the rotation of the can holder by the axis of the generator Gi is not carried out continuously, that is to say in particular when this generator is driven, on the other hand, by the central motor of the sewing machine during its normal operation. Furthermore, it is also obvious that this engine must remain stationary when it is desired to use the generator as a small engine for driving the bobbin winder holder. Finally, it is necessary that, in the latter case, the direction of rotation of the generator rotor is such that the unidirectional coupling described with particular reference to FIGS. 8 and 9 prevents the pinion 8 from driving in rotation. axis 9 of the generator. In this case, it will be a question of supplying the generator with an appropriate polarity voltage.

In order to allow the above functions to be carried out, the invention proposes the implementation of a series of measures of both mechanical and electrical nature which will now be described with particular reference to FIGS. 5 to 7 and 10 .

The interruption of the power supply to the motor M and the connection of the generator G to the voltage source constituted by the ohmic divider of the actuator A are effected by corresponding switching of the electronic switches I _E and I _G (fig. 10) controlled by microprocessor 1 as soon as the user actuates the switch I _b , the tilting pusher of which is visible in FIG. 1.

At this point, it should be noted that, with the machine described, manual actuation of the switch I _b in one direction or the other does not automatically result in the attachment of the motor M or of the armature from the G-Gi generator to their respective energy source gie. Indeed, and according to an interesting feature of the present invention, the machine program is designed in such a way that, when the switch I _{b is} closed or opened, the switches I _E and I _G are not actuated only if the microprocessor receives from the threshold detector DS a signal indicating that the user has released actuator A. Furthermore, even in this case, the microprocessor will not immediately control the actuation of the switches but only after a few seconds (program timing subroutine) so as to allow a significant deceleration of the engine or generator, or even their stopping, this for safety purposes for the benefit of the user.

The interruption of the driving of the bobbin holder Sp, when the user intends to continue sewing, once the bobbin is filled, is carried out by driving the bevel gear 18 from its engagement position with the gear 15 (fig. 6) in a second axial position (fig. 7) in which the pinion 18 is distant from the pinion 15. This interruption can take place by appropriate manual action on the push button of the switch I _b , as it can take place automatically as soon as the can is wound.

To this end, the sewing machine according to the invention is provided with a device whose structural features will now be described.

In essence, this device includes three levers Li, L ₂ and L ₃ mounted articulated around axes 21, 22 and 23 respectively, parallel to the shaft 9 of the generator and fixed to the frame 16. The levers L ₂ and L ₃ are subjected to the action of springs r ₂ and r ₃ tending to tilt the respective levers in angular directions F ₂ and F ₃ (fig. 7).

At its free end, the lever L ₂ has an oblong eyelet 24 in which is freely inserted a rod 25 projecting from the side of the lever L ₁ , parallel to its pivot axis 21. Thanks to this connection, it is possible for the lever L ₂ to switch freely in direction F ₂ , under the action of the spring r ₂ , while commanding a tilting, in direction F ₁ , of the lever L ₁ . Conversely, if the lever Li is tilted in the direction F'i (fig. 6), opposite to the previous one, F ₁ , this lever will cause the lever L ₂ in a rocking movement in the direction F ' ₂ against the spring action r ₂ .

The maximum amplitude of the tilting of the lever L ₁ in the direction F ₁ is fixed by the meeting of a tab 26 that this lever has (figs 2, 4 and 5) with the frame 16. The tilting of this same lever in the direction F ' ₁ is limited by cooperation of the levers L ₂ and L ₃ . It is however chosen sufficient, in one case as in the other, to allow a thrust element 27, integral with the lever L ₁ and in contact with the right end of a tubular extension 18a of the pinion 18, to spread this pinion of the motor pinion 15, during a tilting in direction F ₁ of the lever Li and of bringing it back into the engagement position with the same pinion 15, at the end of a tilting in the opposite direction, F ′ ₁ .

It should also be noted that, in addition to the above function, the tab 26 also exercises that of the control member of the electric switch I _b already cited with reference to the diagram in FIG. 10 and which is shown in perspective in FIG. 5. To this end, the tab 26 is provided with a pusher constituted by a screw 28 capable of acting on a control pad 29 of the switch. The latter will preferably be fixed to the frame 16, at a distance from the tab 26 less than the length of the projecting part of the screw 28, this distance being able to be finely adjusted by more or less pronounced screwing of the pusher 28.

As seen more particularly in Figs 6 and 7, the two levers L ₂ and L ₃ intersect at mid-length. The lever L ₂ comprises a spout 30 having a cutout 31, in the form of a wedge opening respectively towards the articulation axis 22 of this lever and towards the free end, bent at 32, of the lever L ₃ . This lever L ₃ carries a projection 33 extending perpendicular to the figure, up to the lever L ₂ , and whose portion facing the cutout 31 of the spout 30 has a profile homologous to that of this cutout. It should be noted at this point that the lever L ₂ has, in addition, a notch 34 with inclined edges formed in position adjacent to the cutout 31.

The assembly constituted by the cutout 31 and the projection 33 thus forms an exhaust locking member making it possible to maintain the lever L ₂ , and consequently the lever L ₁ , in the tilted position of FIG. 6, in which the pinion 18 is engaged with the motor pinion 15, despite the action of the spring r ₂ acting on the lever L ₂ (maintenance of the drive of the can holder by the generator).

However, if the lever L ₃ is tilted in the direction F ₃ (FIG. 7), this locking ceases to exist as soon as the projection 33 escapes contact with the cutout 31 and enters the notch 34 of the lever L ₂ . In this case, the spring r _{2 will} command the tilting of this lever in direction F ₂ , that of the lever Li in direction F ₁ and therefore the distance of the bevel gear 18 relative to the drive gear 15 (interruption of the drive of the support by the generator-engine).

• - automatiquement, lorsque la cannette placée sur le support Sp est pleine,
• - manuellement, au gré de l'usager.

The tilting of the lever L ₃ in the direction F ₃ can be obtained in two different ways:

• - automatically, when the can placed on the Sp support is full,
• - manually, at the user's discretion.

As already described, the free end of the lever L ₃ is bent at 32; it is engaged in the opening of a window 35 made in the frame 16 opposite the support Sp of can. When the lever L ₃ is in the position of fig. 6, for locking the lever L ₂ , the curved part 32 of the lever L ₃ extends freely in the space between the cheeks and the hub of any can attached to the support Sp. As the can fills , the external surface of the wire winding approaches part 32 of the lever, comes into contact with it and repels it by tilting it in direction F ₃ . It follows that the projection 33 of the lever L ₃ begins to emerge from the cutout 31 of the lever L ₂ by sliding on the portion of the latter adjacent to the notch 34 until the moment when it releases the lever L ₂ and comes to engage in this notch (fig. 7).

The manual control of the tilting in direction F ₃ of the lever L ₃ and, as a corollary, the unlocking of the lever L ₂ can be carried out by action on the rocking pusher 36, controlling the switch I _b (FIGS. 1 and 5), which is articulated on the frame 16 thanks to an axis 36a oriented parallel to the tilting axis of each of the three levers Li, L ₂ and L ₃ . This pusher can be driven in two symmetrical positions, in each of which it can be held stably by a tension spring 37 stretched between the beam 36b of the pusher and the end 38a of a support 38 integral with the armature 16. It will be noted, in this regard, that this support is such that its end 38a is located opposite the axis 36a of the pusher relative to the end for fixing the spring 37 to the beam 36b. The flail 36c of the pusher is provided with a support tab 36d in contact with a rod 32a projecting laterally on the lever L ₃ , in particular when this lever occupies the position illustrated in FIG. 6, for locking the lever L ₂ (figs 4 and 5). Under these conditions, the pusher 36 occupies the position visible in FIG. 2, that is to say in which the beam 36c protrudes for a large part above the frame 16 while the beam 36b is almost flush with the upper face of this frame. It will suffice to exert pressure on the beam 36c so that the latter drives in its stroke the rod 32a of the lever L ₃ thus determining the tilting of the latter in direction F ₃ (fig. 7). As, in this case, the unlocking of the lever L ₂ is obtained, it follows that the action thus exerted on the beam 36c of the pusher 36 leads to the separation of the pinions 15 and 18 and, therefore, to the stopping of the can C. In addition, since the lever L ₁ has tilted in the direction F ₁ , the pusher 28 moves away from the switch I _b which then moves to the open position which produces the tilting of the electronic switches I _E and I _G in their second functional position, in which the motor M can be supplied with current as soon as the user acts on the actuator A and the generator G is attached to the circuit for adjusting the speed of the motor.

The rocker plunger 36 also makes it possible to "arm" the mechanism described, that is to say to ensure that the levers L ₁ , L ₂ and L ₃ are brought back to the position illustrated in FIG. 6 and the pinion 18 for driving the can is brought into engagement with the pinion 15. In fact, and as can be seen more particularly in FIGS. 4 and 5, the lever L ₁ is provided with a spout 39 making projection under this lever, next to the tab 26 already mentioned, and partially extending under the beam 36b of the pusher 36, at a short distance from the latter, in particular when this pusher occupies the symmetrical tilted position of that illustrated in FIG . 2. It will therefore suffice to exert a directional push F ₄ (FIG. 5) on the beam 36b of the pusher to drive the lever L ₁ in the direction F ' ₁ by action on the spout 39 of this lever. It will be noted that, in doing so, in addition to causing a corresponding tilting, in the direction F ' ₂ , of the lever L ₂ , there will be a movement of the lever L ₃ in the direction F' ₃ under the action of its return spring r ₃ , movement which will end, as described, when the projection 33 of the lever L ₃ comes into contact with the edges of the cutout 31 of the lever L ₂ .

It will also be noted that the tilting capacity, in one direction or the other, of the pusher 36 is limited by encountering the free end of one or the other beam 36b and 36c of the rocker with the edge of the opening of the frame 16 in which this pusher takes place.

The second embodiment (fig. 12) of the sewing machine according to the invention is distinguished from the first (fig. 10) only by the way in which the generator G can be electrically connected to the actuator A by winding phase of a C can.

Thus, in this embodiment, the armature of the generator remains permanently attached, on the one hand, to the input, shown positively, of the amplifier Ci and, on the other hand, to the output of the amplifier A ₄ itself attached to the actuator A, the activation and deactivation of this amplifier being controlled by an electronic switch l ' _G , actuated by the microprocessor 1 when the switch I _b (analogously to what happened with the switch I _G in the case of the embodiment of fig. 10).

Indeed, the electronic switch l ' _G is, moreover, attached to the ground so that, in the closed position, no signal will be output by the amplifier A ₄ , whatever the position of the actuator A. A signal will, on the other hand, be delivered by the amplifier A ₄ if the switch l ' _G is open, provided, of course, that the actuator A is carried in a position different from that of rest.

In this case, the actuation of the electronic switch l ' _G is synchronized with that of the electronic switch I _E and is controlled, as for the latter, by the microprocessor 1, on the basis of the information received from the switch I _b .

Thus, if the switch I _b is brought to the closed position, the microprocessor will control the switches I _E and the _G in the opening direction. If, on the other hand, the switch I _b is actuated at the opening, the switches I _E and the _G will be controlled in the closing direction.

As can be seen, despite its high level technical performance, the double-action clutch device which has just been described is both compact and easy to manufacture. All of its parts, which can be produced in particular by injection of an appropriate plastic material, are only subjected to mechanical efforts of low intensity since the slack These parts are controlled from the generator G, the power of which it is capable of delivering in engine speed is reduced: it follows that, in addition to the advantages mentioned above, the fact that the device The clutch described is guaranteed to last a long time even in the case of intensive and repeated use.

It will also be noted that the implementation of the invention described requires only a slight adaptation of the traditional electronic circuit of an electric sewing machine, with computerized control, without appreciable modification of the structural complexity inherent in such a circuit and, hence, its cost price.

Although the invention has been described with reference to a sewing machine, with computerized control, in which the adjustment of the working speed is effected by direct action on the control motor, it is obvious that all of the principles exposed could be used, mutatis mutandis, in a machine in which this regulation will not be carried out on the engine itself but on certain mobiles located downstream of this engine like, for example in the case of the machines illustrated in the Swiss patents 635 382 and from the United States of America 4,377,778 cited above.

Claims (13)

1. An electric sewing machine with computerized control in which the speed of rotation of at least some moving parts is dependent on the action of an electronic regulator of which the detecting circuit comprises at least one tacho generator (G-Gi) which is kinematically connected to said moving parts and is intended to emit a voltage representative of their instantaneous speed of rotation, and at least one source of reference voltage (2) having a value which varies with the position occupied at any moment by an actuator (A) of the machine, this regulator acting on the speed of rotation of the moving parts by permanent comparison of said voltages and in which a device permits the user to wind thread on an empty bobbin (C), this device comprising a rotating support on which the bobbin may be detachably fixed and a driving mechanism for setting the support into rotation, the machine being characterized by the fact that this mechanism comprises

a) all the members constituting said generator (G-Gi),

b) a double action clutch (E_A) enabling the rotor of the generator (G-Gi) to be coupled mechanically, either to said moving parts in a first operating position, or to said rotating support in a second operating position of the clutch,

c) change-over means connected to this clutch, enabling the generator armature to be connected to a supply voltage source in order to allow electromagnetic driving of the rotor when the coupling occupies its second operating position and to interrupt this connection in the first operating position of the clutch,

d) means (I_E) interrupting the driving of said moving parts during winding of the bobbin.

2. A sewing machine according to Claim 1, characterized in that said change-over means are arranged so as to allow the generator armature to be connected, either to the detecting circuit of said regulator in said first operating position of the clutch, or to said supply source in the second operating position thereof.

3. A sewing machine according to Claim 1 or 2, in which said moving parts are permanently connected to a driving motor, said regulator acting directly on the speed of rotation of the motor, characterized in that the means for interrupting the drive of the moving parts are constituted by a switching circuit acting on the current supply of the motor, this circuit being coupled to the clutch so as to cut off this supply while this clutch occupies its second operating position.

4. A sewing machine according to Claim 1 or 2, comprising an--electric motor for driving said moving parts, characterized by means for controlling the instantaneous position occupied by the actuator, other means preventing any operation for connecting said electric motor and/or the generator armature to their respective source of supply in all positions of the actuator other than the rest position.

5. A sewing machine according to Claim 1 or 2, in which said generator is driven by said moving parts by means of gear wheels comprising at least one crown wheel which is kinematically connected to the moving parts and at least one pinion wheel meshing with this crown and integrally connected to the shaft of the generator, characterized in that this pinion wheel is mounted on the shaft of the generator by means of a unidirectional joint constituting one of the elements of said clutch device, this clutch also comprising second gear wheels which are kinematically connected to the shaft of the generator, a second pinion wheel which is angularly integrally connected to a pivoting pin bearing said bobbin support, this pinion wheel also being mounted so as to slide on this pin and being capable of being guided by elastic means and by sliding on the pin in engagement with the last moving part of said second gear wheels, a bistable rocker comprising a push rod capable of acting on said second pinion wheel in order, either to remove it from said moving part of the second gear wheels, by sliding on the pin of the bobbin support and away from said elastic means when the rocker is guided in a first stable position, or to cause said elastic means to act on this second pinion wheel, when the rocker is in its second stable position.

6. A sewing machine according to Claim 5, characterized in that the shaft of the generator and that of the bobbin support are contained in orthogonal planes, the last moving part of the second gear wheel and the pinion wheel connected to the bobbin support being bevel gears.

7. A sewing machine according to Claim 6, characterized in that the rocker comprises a first level of which an intermediate portion of its length forms said push rod, this lever being mounted so as to rock in a plane extending transversely to the shaft of the generator, a second lever articulated at a distance from the first lever and mounted so as to rock in parallel with the rocking plane of the first lever, the free end of this second lever being connected to the first lever by a linking member allowing the first lever to rock about its pivot pin and at the same time to slide in the longitudinal direction of the second lever, the respective movement of each lever thus being kinematically dependent on that of the other lever, said second lever being subjected to the action of an elastic means tending to lead the first lever into a first limiting angular position corresponding to said stable second position of the rocker, detachable means for locking with escapement being connected to said second lever and being capable of holding this lever away from said elastic means in a second limiting angular position which corresponds to said first stable position of the rocker.

8. A sewing machine according to Claim 7, characterized in that said locking means comprise a third lever mounted pivotally about a pin situated between the pivot pins of the two other levers and articulated in a plane parallel to the rocking planes of these levers, this third lever being subjected to the action of its own elastic means tending to cause it to rock in an angular direction opposed to the rocking direction imposed on the second lever by the respective elastic means, said third lever being orientated between the other two levers so as to have its own central portion pass in the vicinity of a central portion of the second lever, and in that, on said central portion, the second lever has a corner-shaped cutout opening towards the axis of articulation of this lever and towards the free end of the third lever respectively, this third lever in turn having, on a portion close to said cutout of the second lever, a projection having a shape matching that of this cutout and in engagement within this cutout under the influence of the elastic means connected to the third lever and in a first limit angular position thereof when the second lever is led into its angular position corresponding to the second stable position of the rocker, the third lever thus causing this rocker to be locked in this stable position.

9. A sewing machine according to Claim 8, characterized by a notch having edges which converge in the direction of the base of this notch made in the second lever in a position adjacent to said cutout, this notch being capable of receiving said projection of the third lever at least in a second end angular position thereof corresponding to said first stable position of the rocker.

10. A sewing machine according to Claim 9, characterized by means for controlling the rocking of the third lever from its first end angular position into its second end angular position and vice-versa.

11. A sewing machine according to Claims 3 and 10, in which said circuit comprises an electric switch and a rocking push member with two arms which controls the position of this switch, characterized in that the rocking plane of the push member is parallel to the rocking planes of said first, second and third levers and in that this push member is arranged in such a way that, by rocking it in a first angular direction, one of its arms strikes the free end of the first of said levers thus allowing this lever to be pushed and to be removed from its end angular position corresponding to said second stable position of the rocker and bringing it into its other end position corresponding to the first stable position of this rocker, rocking of the push member in a second annular direction opposed to the previous one bringing the other arm of this push member to rest on a portion of the third lever, at least during a portion of this rocking, this third lever thus being removed from its first end angular position, the locking of said second lever, and being guided into its second and angular position in which the projection of the third lever is engaged in the notch in the second lever.

12. A sewing machine according to Claim 11, characterized in that the rocking push member engages on the switch control member by means of a thrusting element connected to the first lever.

13. A sewing machine according to Claim 9, characterized in that the free end of said third lever forms a feeler and extends substantially in the plane of the axis of the bobbin support, this end of the third lever being profiled in such a way that, when this lever is in its limit angular position corresponding to the locking of the second lever, said end extends at least in part into the space between the lateral flanges of any empty bobbin fixed on the bobbin support, this feeler being pushed outside this space as the bobbin is wound by contact with the thickness of thread wound on the bobbin until it causes rocking of the third lever which is sufficient to unlock the second lever and, therefore, to remove said second pinion wheel which is angularly connected to the pin of the bobbin support of the second gear wheel driven by the shaft of the generator.

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