EP1257702B1 - Method and knitting machine for rectilinear knitting to form a tubular seamless knitted material - Google Patents

Abstract

The invention concerns a knitting machine comprising two needle beds (1, 2, 43, 44) for guiding knitting needles (3), means for selecting said knitting needles (3), carriages (4, 40) for moving the selected knitting needles and members guiding (10) the knitting thread (52). The method consists in arranging the needle beds (1, 2, 43, 44) so that the needles (3) of a needle bed (1; 43) in their normal knitting travel do not cross the needles of the other needle bed (2; 44), in moving the carriages in one direction along each needle bed (1, 2, 43, 44), the displacement directions of said carriages (4, 40) along their respective needle beds being opposite relative to each other and in transferring the thread (52) from the needles (3) of one needle bed (1, 43) to those of the other needle beds (2, 44), each time said thread (52) reaches the end of the selected needles (3).

Description

The present invention relates to a method for forming a seamless tubular knit on a straight knitting machine comprising two needle guiding needles for knitting needles, means for selecting these knitting needles, trolleys for moving the selected knitting needles. and guiding members of the knitting yarn, and a straight knitting machine for carrying out this method.

Conventional flat knitting machines could allow to knit seamless tubular articles, with some modifications, including articles formed of two tubular elements joined together in a single tubular element, such as pants. However, they do not make it possible to produce such articles with a sufficiently tight knit to make a pant fabric. They also do not allow production on economically viable conditions, as the speed of production would be reduced. Circular looms do not make it possible to produce two tubular elements side by side, or to produce tubular elements of variable diameters, or else at the expense of the homogeneity of the knitting, for example by varying the tension on the thread, the tightening of the meshes etc.

Various solutions have been proposed, in particular in the EP 0 412 944 which relates to a trade in which the cams of the control of the needles are fixed to two rings of cams, so that this craft does not allow to knit tubular elements of variable diameters. Moreover, this profession does not describe any means for transferring the thread from one needle bed to another and simply refers to the US 4,689,971 which shows only one wire arranged on one side of a needle and can be knitted by the needles of the other needle by the fact that the needles of the two needle beds intersect.

In the solution proposed by the EP 0 552 588 , the wire is not separable from the carriage. As to DE 18 031 it only knits a tubular element.

The US 3,456,459 refers to a circular loom, having a cylindrical needle bed associated with a tray. The cylindrical needle bed is divided into four areas with needle grooves controlled by a ring of cams and separated by spaces. Wire guides are mounted on a circular rail and are adapted to move alternately in both directions depending on the direction of movement of the cams. This craft is designed to function as a straight line craft, but it does not allow for decreases or increases, the race of the wire guides being constant. The US 4,724,687 refers to a yarn feeding apparatus for a tubular fabric knitting machine in which the needles of the two needle beds intersect and in which only the needles of a needle bed are working while those of the other needle bed are at rest and vice versa. The production of such a craft is therefore extremely low.

The object of the present invention is to produce a seamless tubular knit on a straight knitting machine, which can overcome, at least in part, the aforementioned drawbacks.

For this purpose, the present invention firstly relates to a method for forming a seamless tubular knit on a straight knitting machine of the aforementioned type, as defined by claim 1.

Preferably, this method relates to the formation of two tubular bodies joined together in a single tubular body, allowing to achieve a seamless pants.

This invention also relates to a knitting machine for carrying out the knitting process, as defined by claim 3.

This invention has the advantage of allowing the manufacture under economic conditions of a product according to the document EP-A-0 905 298 .

It should be noted that one of the advantages of the method that is the subject of the invention lies in the fact that the diameter of the tubular part or portions of this article may vary so as to give it the desired shape.

Indeed, as will be appreciated in the course of the description which follows, the knitting process according to the invention can not be implemented on a conventional straight knitting machine, but requires a new concept of trade rectilinear, explaining that only by imagining a new concept of knitting, radically different from that usually used in straight knitting machines, the invention was born. It was indeed necessary to create a concept for knitting two separate knit layers, one on each needle bed by continuously joining them by a transfer of the knitting threads from one needle bed to the other, thus allowing the formation of a tubular element without sewing. From this principle, it becomes possible to imagine the simultaneous realization of two tubular elements side by side, which can then be combined into a single element tubular by selecting the needles separating the two tubular elements.

• La figure 1 est une vue en perspective d'un métier à tricoter selon la première forme d'exécution;
• la figure 2 est une vue en coupe transversale selon la ligne II-II de la figure 1;
• la figure 3 est une vue en élévation latérale de la figure 1;
• la figure 4 est une vue partielle à plus grande échelle d'un détail de la figure 1;
• la figure 5 est une vue de dessus de la figure 1, illustrant uniquement le système de transfert des guides-fils;
• la figure 5a est une vue agrandie d'un détail de la figure 5;
• la figure 5b est une vue en perspective de la figure 5a;
• la figure 6 est une vue en élévation de la figure 5;
• la figure 6a est une vue d'un détail de la figure 6;
• la figure 6b est une vue de dessus du détail de le figure 6a;
• la figure 6c est une vue agrandie d'un détail de la figure 6;
• la figure 7 est une vue de dessus partielle de la figure 1 ne montrant que les organes relatifs au réglage de la largeur du tricot tubulaire;
• la figure 7a est une vue agrandie d'un détail de la figure 7;
• la figure 8 est une vue partielle de dessus d'un détail d'un chariot de commande des aiguilles de tricotage, montrant un dispositif de déplacement de ce chariot par rapport à son mécanisme d'entraînement;
• la figure 9 est une vue en élévation latérale du métier à tricoter selon la seconde forme d'exécution;
• la figure 10 est une vue selon X-X de la figure 9;
• la figure 11 est une vue de dessus de la figure 9;
• la figure 12 est une vue selon XII-XII de la figure 9;
• la figure 13 est une vue selon XIII-XIII de la figure 12;
• la figure 13a est une vue de dessus de la portion agrandie de la figure 13;
• la figure 14 est une vue de dessus de la figure 13;
• la figure 15 est une vue semblable à la figure 14 d'un second poste de transfert de fil;
• la figure 16 est une vue agrandie d'un guide-fil;
• la figure 17 est une vue d'une variante du guide-fil illustré par la figure 16.

The invention will be better understood with reference to the description which follows and to the accompanying drawings which illustrate, schematically and by way of example, two embodiments of the method which is the subject of the present invention, relating to two forms. execution of the trade also object of this invention.

• The figure 1 is a perspective view of a knitting machine according to the first embodiment;
• the figure 2 is a cross-sectional view along line II-II of the figure 1 ;
• the figure 3 is a side elevation view of the figure 1 ;
• the figure 4 is a partial view on a larger scale of a detail of the figure 1 ;
• the figure 5 is a top view of the figure 1 , illustrating only the wire guide transfer system;
• the figure 5a is an enlarged view of a detail of the figure 5 ;
• the figure 5b is a perspective view of the figure 5a ;
• the figure 6 is an elevation view of the figure 5 ;
• the figure 6a is a view of a detail of the figure 6 ;
• the figure 6b is a top view of the detail of the figure 6a ;
• the Figure 6c is an enlarged view of a detail of the figure 6 ;
• the figure 7 is a partial top view of the figure 1 showing only the organs relating to the adjustment of the width of the tubular knit;
• the figure 7a is an enlarged view of a detail of the figure 7 ;
• the figure 8 is a partial top view of a detail of a knitting needle control carriage, showing a device for moving this carriage relative to its drive mechanism;
• the figure 9 is a side elevational view of the knitting machine according to the second embodiment;
• the figure 10 is a view according to XX of the figure 9 ;
• the figure 11 is a top view of the figure 9 ;
• the figure 12 is a view according to XII-XII of the figure 9 ;
• the figure 13 is a view according to XIII-XIII of the figure 12 ;
• the figure 13a is a top view of the enlarged portion of the figure 13 ;
• the figure 14 is a top view of the figure 13 ;
• the figure 15 is a view similar to the figure 14 a second wire transfer station;
• the figure 16 is an enlarged view of a wire guide;
• the figure 17 is a view of a variant of the wire guide illustrated by the figure 16 .

The knitting machine illustrated by the figure 1 is a rectilinear loom comprising two needle beds 1, 2, which form either two parallel planes or, as illustrated in this figure 1 , the planes of these needle beds form between them an acute angle such that the knitting needles 3, in their normal course of knitting, do not intersect, as illustrated by the figure 2 .

It is specified that only those parts of the art necessary for understanding the invention have been represented. The parts common to this type of trade, well known to those skilled in the art and which are not part of the present invention have not been represented. This is particularly the case of the selection mechanism of the knitting needles 3, as well as the cam control mechanisms of the needles secured to the carriages.

A plurality of carriages 4 are arranged along the needle beds 1, 2. These carriages 4 are integral with a chain or drive belt 5. This drive chain 5 forms a closed loop by rotating around two drive disks 6, rotatably mounted around two respective vertical shafts, one of which 7 is visible on the figure 1 . The carriages, integral with this drive chain 5, therefore always move in the same direction. In the example described, this direction is that of the arrow F, so that these carriages 4 pass successively from one needle 1 to the other needle 2 and vice versa.

A guide rail 8 forms a closed loop whose plane is parallel and located above the closed loop, formed by the driving chain 5. Sliding supports 9, illustrated in more detail by the Figures 6a, 6b , are engaged with the guide rail 8 and are slidable freely along this rail. A wire guide 10 is suspended from each sliding support 9. For this purpose, the upper end of the wire guide 10 terminates in a hooking element 10c of semicircular shape, while the sliding support 9 has a groove longitudinal attachment 9a open at both ends, to allow the fastening element 9a to exit from the rear of the longitudinal groove 9a and to return from the front, considering the direction of movement of the sliding support 9 .

Each carriage 4 carries a bracket 11 whose horizontal arm 11a extends just below the guide rail 8. This horizontal arm 11a constitutes a slide in which two pushers, an upper pusher 12 and a lower pusher 13 are slidably mounted. each of these pushers being secured to an ankle 12a, respectively 13a. The role of these pushers 12, 13 is to push the sliding supports 9 and the wire guides 10 along the guide rail 8. The upper pusher 12 ends with a oblique portion 12b for pushing the son-guides during the transfer operation son-guides, as will be seen later.

The knitting machine also comprises transfer members 14 of the thread guides 10 of a knitting needle bed 3 associated with one of the needle beds 1, 2 to the knitting needle bed 3 associated with the other of these needle beds. 1, 2. Each of these transfer members 14 has two parts 14a, 14b ( figure 5a ), forming between them a guide groove 16, each of the two parts being integral with an arm 15a, 15b of a suspension member 15 ( figure 1 ). The outlet end of the guide groove 16 is closed by a retractable valve 16a, retained by a spring 16b and used to retain the wire guide 10 during its transfer from a bed of knitting needles 3 of the one of the needle beds in knitting needles 3 on the other of the needle beds.

The wire guides 10 comprise, along their rod, a guide portion 10a whose section is ovalized to facilitate guiding in the guide groove 16. The top of this guide portion 10a has a projection 10b intended to come into contact with the upper face of the transfer member 14, thereby defining the vertical position of the wire guide 10. Advantageously, the upper face of the transfer member 14 is shaped as a cam to lift the wire guide 10 during the transfer and put it out of range of the knitting needles 3 and to bring it back to its initial level after the transfer.

As can be seen from the figure 1 , four transfer members 14 are arranged along the needle beds 1 and 2. The two transfer members 14 arranged at both ends are oriented so that the ends of their guide grooves 16 look inward, that is to say that they face each other. The suspension members 15 of the two other transfer members 14 located between those ends are both integral with a drive member 17 designed to orient them angularly, as will be seen later. As we also see on figures 1 , 6 and 7 , each of the suspension members 15 is also connected to an adjusting nut 18a, 18b, 18c, 18d engaged with a threaded rod 19 having four sections 19a, 19b, 19c, 19d, threaded with not reversed with respect to each other . One end of this threaded rod 19 is integral with an adjusting member 20, which may advantageously be a stepper motor. The role of this adjustment member 20 is in particular to adjust the spacing between the transfer members 14.

The adjusting nuts 18a, 18d carry an arm 77a, respectively 77d, while the adjusting nuts 18b, 18c each carry two arms 77b, respectively 77c.

Each arm 77a, 77d located at one of the ends of the needle beds 1, 2 carries a cam 21a, 21b ( figures 1 and 7 ) intended to engage with a pin 13a of the pusher 13. Each arm 77b, 77c located in the middle part of the needle beds 1, 2 is associated with two cams 21c, 21f, respectively 21e, 21d intended to engage with this same ankle 13a, for the purpose that will be explained later.

As shown in the enlarged view of the figure 7a , the cam 21d, carried by the arm 77c, is integral with the end of an arm 81, articulated to the end of the arm 77c. A transmission belt 78 connects a pulley 79, integral with the drive motor shaft 17, to a pulley 80 secured to the axis of articulation of the arm 81. Thus, the cam 21d carried by the arm 81 can be brought into two positions, an active position illustrated in phantom on the figure 7a and an inactive position shown in solid line on this same figure 7a . The other cams 21a-21f are actuated in the same manner as described above for the cam 21d.

Each end of the guide rail 8 terminates in a greatly enlarged portion 8a, 8b. At the entrance and the output of each of these enlarged portions two cams more or less superimposed 22a, 22b, 22c, 22d are arranged to engage with the pins 12a, 13a of the pushers 12 and 13. The role of the cams 22a, 22c located at the entrances of the parts respective widened 8a, 8b, is to move the pushers 12, 13 to clear the center of each of these widened portions 8a, 8b to allow wire feeding of the wire guides from two sets of four coils 23 (in this example) each carried by a rotary creel 24 integral with a shaft 25.

A bevel gear transmission connects this shaft 25 to the shaft 26 of a geared motor M located at each end of the loom and which, by two respective transmission belts 27 also drive the shafts 7 disks 6 around which The axes 25 of the creels each still carry a reference 28 in engagement with a transmission belt 29. A transmission shaft 30 transmits the movement received by the belt 29, with the aid of FIG. a transmission belt 31 to a rotary wire guide 32. With this arrangement, the relative speeds of the creel 24 and the rotary wire guide 32 can be controlled so that the various son do not intermingle.

The figure 8 further illustrates a device for the relative movement between the carriage 4 and the drive chain 5. For this purpose, the carriage 4 is connected to the drive chain 5 via a slide 33 secured to the carriage 4 and a slider 34 secured to the drive chain 5. A servomotor 35 serves to rotate a worm 36 engaged with the slider 34 to move it along the slide 33. The power supply of the servomotor is carried out by a feed rail 37 with which a shoe 38 comes into sliding contact.

Since the knitting needles 3 do not intersect, it is necessary to provide maintaining knitting during knitting. Such organs 39 are visible on the figure 4 . It can be seen that they are constituted as a kind of combs allowing the knitting needles 3 and the knitting yarns to pass. These holding members 39 each rest on a support bar 39b. As we see on the figure 4 the portions 39a of the holding members which extend above the respective upper edges of the needle beds 1, 2 are thinned, thus leaving room for the formation of the knit stitches during the descent of the knitting needles 3 in the grooves for guiding the respective needle beds 1, 2.

It is thanks to these holding members 39 that it is possible to increase the clamping force on the stitches so as to produce a knit with denser stitches.

The figure 16 illustrates a detail of the guide portions of the guide wire 10 which each comprise a free ring 10e held between two annular stops 10d. This free ring 10e has a diameter substantially greater than that of the wire guide rod 10, but less than that of the two annular stops 10d, so that it is free to move between these stops 10d. With this arrangement, the wire guide 10 can rotate relative to the direction of the wire 52. Thus, when the wire guide 10 is transferred from one needle bed to another by the transfer members 14, it is a rotation of 180 ° but, thanks to the free ring 10e which retains the wire 52, the rotation of the wire guide 10 has no effect on the wire 52 which can rotate relative to the wire guide 10 to keep the same orientation defined by the position of the wire feed spool.

The mode of implementation of the knitting machine which has just been described is as follows:

To explain this operation, we will follow a wire guided by a guide wire 10 from the moment when it is at the output end of the guide groove 16 of the transfer member 14 which is located at the end right of the needle bed 1 observing the figure 1 . At the outlet end of this guide groove 16, this wire guide is retained by the valve 16a. When a sliding support 9, pushed on the guide rail 8 by the pushers 12, 13 integral with the bracket 11 fixed to the carriage 4, comes directly above the outlet of this guide groove 16, it meets the body hooking 10c of the guide wire 10 retained at the exit of this guide groove 16 by the valve 16a. This attachment member 10c enters through the front of the hooking groove 9a until it abuts against the pushers 12, 13 which drive the sliding support 9 along the guide rail 8. From this moment, the wire guide 10 advances with its wire as the carriage 4 moves towards the needle bed 1.

During its movement, the knitting cams (not shown) of the carriage 4 engage the needles 3 which follow one another along the needle bed 1, thus raising and lowering these needles which knit the thread that the guide presents them -fil 10.

When the wire guide 10 arrives opposite the transfer member 14, that is to say, in the example chosen, the second of the four transfer members 14 starting from the one at the right end of the needle bed 1 on the figure 1 its guide portion 10a meets the inlet of the guide groove 16 of the second transfer member. Simultaneously, the pin 13a meets the cam 21d ( figure 7 ) which removes the pusher 13 slightly backwards, thus releasing the rear end of the hooking groove 9a of the sliding support 9, only the pusher 12 remaining, by its inclined part 12b, in contact with the thread guide 10.

The guide portion 10a of the guide wire 10 being engaged in the guide groove 16 of the transfer member 14, the wire guide 10 changes direction, while the sliding support 9, in engagement with the rail 8, continues to follow a trajectory parallel to the needle bed 1. Thanks to his face inclined 12b, the pusher 12 can thus give a pulse to the wire guide 10 as it leaves the hooking groove 9a of the sliding support 9, from the rear thereof. This pulse of the inclined face 12b of the pusher 12 has the effect of pushing the wire guide 10 into the guide groove 16 of the transfer member 14, until it abuts against the check valve 16a, or he waits to be picked up by another carriage 4 pushing another sliding support 9.

As for the carriage 4 and the sliding support 9 which have just separated from the guide wire 10 engaged in the transfer member 14, it continues its movement along the needle 1 in the direction of the arrow F. Immediately after have left the second transfer member 14 from the right end of the needle bed 1 ( figure 1 ), the sliding support 9 driven by the carriage 4 passes against the third transfer member 14, rotated 180 ° about the suspension member 15, so that the path of the guide groove 9a of the sliding support 9 passes through the output end of the guide groove 16 of the transfer member 14, causing the passage guide wire 10 waiting at this end.

The same knitting process as that described above takes place until the wire guide 10 meets the entrance of the guide groove 16 of the fourth transfer member 14 which is located at the left end on the figure 1 1. At the same time, the cam 21a ( figure 7 ) moves the pusher 13 with the aid of the pin 13a and the inclined portion 12b of the pusher 12 gives the wire guide 10 a pulse to transfer it to the needle bed 2.

The carriage 4 then arrived at the left end ( figure 1 ) of the bed 1 and it is now driven by the chain 5 towards the bed 2 turning around the disc 6. As for the sliding support on the rail 8, it addresses the enlarged portion 8a of the guide rail 8. At the beginning of this widened part, the pegs 12a, 13a of the pushers 12 and 13 meet two cams 22a which remove these pushers 12 and 13 towards the outside of the loop 8a in order to disengage the center and allow the passage of the knitting son passing from rotary wire guide 32 to the wire guides 10.

Once the carriage 4 completes its rotation, the pegs 12a, 13a meet a cam 22b ( figure 7 ) which returns the pushers 12 and 13 in their initial position, so that when the hooking groove 9a of the sliding support 9 passes just above the output of the guide groove 16, the attachment member 10c the guide wire 10 is introduced into this hooking groove 9a and is driven along the rail 8, with the sliding support 9, by the pushers 12 and 13.

Taking into account the transfer of the knitting yarn without cutting this thread, a bed of knitting needles 3 of one of the needle beds 1, 2 to the bed of knitting needles 3 of the other of these needle beds, turning constantly in the same direction, a tubular knit is formed and, as there are two pairs of transfer members 14 arranged along the needle beds 1 and 2, it is thus possible to form two elements of tubular knits side by side, which can advantageously make up the two legs of pants in underpants or seamless tights. Once the length of the legs is reached, it is sufficient to select the knitting needles 3 located between the two transfer members 14, using the conventional selection means, not shown because they do not belong of the present invention.

At the same time as the aforementioned knitting needles 3 are selected, the two transfer members 14 are rotated by 90 ° with the aid of the motors 17, so that the wire guides 10 can no longer engage in the guide grooves 16 and only the transfer members 14 placed at both ends of the needle 1, 2 are still in use. From then on, the two knit elements tubular legs forming pants pants or pantyhose are combined into a single tubular element forming the top of the trousers pants or tights. At the same time, since each knitting yarn makes from this moment the complete turn of the needle beds over their whole width and not only over half of this width, the motor-reduction gearboxes M will drive the cannons 24 at speeds halved.

Since the speed at which the carriages 4 are driven by the endless drive chain 5 is constant, the servomotors 35 associated with each carriage 4 make it possible to reduce or increase the speed of movement of these carriages 4 to enable synchronize them. Indeed, in the example described, each creel 24 carries four feeding reels 23 of knitting yarn, which corresponds to four threads per knitted leg and eight threads when knitting the top of the pants. Given the increases and decreases in the width of the knit, it may be necessary to change the speed of the carriages 4 to take the wire guides 10 at the output of the transfer members 14.

However, before the carriage 4 begins to rotate around the drive discs 6 to work with the opposite needle, the servomotor 35 must return the carriage 4 to the zero position, that is to say in the position where it is not possible. found neither in advance nor behind the reference distance between the carriages 4.

When the knitting needles 3 are selected in order to increase or reduce the diameter of the knitted tubular member or elements, it is necessary to modify the positions of the transfer members 14 so that they follow these changes in diameter. This adjustment is performed by the worm 19 and the stepping motor 20. Due to the inversions of the threads of the various sections 19a, 19b, 19c, 19d of the worm, when knitting the two legs of the pants, following the direction of rotation of the screw 19, the transfer members 14 delimiting in pairs the two legs of the pants are moved together or away from each other. Similarly, when knitting a single tubular element forming the top of the pants, where the two transfer members 14 located in the middle part of the needle 1, 2 are disabled, as explained above, the two transfer members 14 located at the ends of these needle beds 1, 2 are brought together or removed from each other in the direction of rotation of the adjusting screw 19.

In a variant illustrated by the figure 17 to prevent winding of the wire 52 around the rotating wire guide, when it follows the tubular shape of the knit and thus changes orientation with respect to the portion of wire between the movable wire guide 10 and the guide -fil 32, one can also use a tubular thread guide 10 '. The wire 52 enters through one end of the tube of the wire guide 10 'and exits through the other end. Such a wire guide 10 'can therefore change orientation relative to the fixed wire guide 32 without the wire wraps around him. Such a wire guide 10 'may advantageously comprise two disks 10'f and 10'g, one 10'f serving to support the wire guide 10' on a carriage (not shown) and the other to come into engagement with a transfer arm (not shown).

The second embodiment will be described now in relation to the Figures 9 to 15 . Several of the modifications described in connection with this embodiment can be used in the previous embodiment. Likewise, several of the elements described in connection with the first embodiment can be used in the second embodiment.

The fundamental difference between these two embodiments lies in the fact that instead of moving in a horizontal plane, the carriages 40 according to the second embodiment move in two vertical planes, so that this form of execution requires twice as many trolleys than the first form of execution. Another noticeable difference is in the creels for the knitting yarn feed bobbins.

The figure 9 shows an endless drive chain 41 forming a closed loop around two wheels 42 with horizontal pivot axes. A second identical chain forms a second parallel loop, disposed on the other side of the two vertical needle beds 43, 44, as can be seen in particular on the figure 10 . The carriages 40 are each connected to one of the chains 41 by an axis 40a transverse to this chain, allowing them to pivot. These carriages 40 each still carry two guide pins 40b intended to engage two guide rails 45 arranged at both ends of the closed loop described by the carriages 40. These carriages 40 thus comprise three guide points, the axis 40a and the dowels 40b, so that, thanks to the guide rails 45, they can move from the upper horizontal part of their path to the lower horizontal part, staying constantly in a horizontal position as well passing from top to bottom of their trajectory only from the bottom up.

Unlike the previous embodiment in which the transfer of the thread from one needle bed to another takes place by transferring the wire guides, in this embodiment, only the wire is transferred, the wire guides 46 being integral with the carriages 4C. As illustrated by figures 13 , 13a and 14 , the wire guide 46 is fixed to the carriage 40 by a pillar 47 around which a tubular body 48 pivots. This tubular body 48 terminates in a pinion 49 at its lower end and in a wire retaining member 50 constituted by a member provided with four radial notches 50a recalling a Maltese cross, at its upper end. The pinion 49 meshes with a reference 49a pivotally mounted on the carriage 40. The upper end of the pillar 47 carries a locking member 51 of the knitting yarn 52. This locking member 51 is pivotally mounted on this pillar 47 and is normally applied against a stop 53 integral with an arm 53a itself secured to the pillar 47. A return spring 54 constantly tends to keep the locking member applied against the stop 53.

Transfer Stations 55 ( figures 12 , 13 , 14 and 15 ), as the transfer members 14 of the first embodiment are four in order to transfer the knitting yarn from one needle bed to another at each end of the knitting stroke, corresponding to half of a portion of tubular knit. The two transfer stations 55 located in the middle part of the needle beds can be put out of service to allow the knitting of the trouser upper. As in the case of the transfer members 14, the transfer members 55 of the second embodiment are engaged with adjusting screws 19 ', 19 ", controlled by motors 20', 20", to vary the width knitting.

Each transfer station 55 comprises two racks 56 located on the respective trajectories of the two referrals 49a. A clearance cam 57 is still disposed in the path of a portion 51a of the locking member 51 of the knitting yarn 52, on the side where the yarn must be clear of the guide wire 46 to be transferred to the other bed. In the example described, this release cam 57 is on the left with reference to the figure 13 .

The frame of this transfer station 55 further comprises two transfer slides 58, 59, each carrying two stops 58a, respectively 59a intended to limit their respective strokes. Two actuating members 60 serve to actuate these slides from one stop to the other and vice versa. The free end of the transfer slide 58 is still secured to a pusher 58b provided with an opening for the passage of the other slide 59. The pusher 58b can be moved by the transfer slide 58 to an abutment surface 55a secured to the frame of the transfer station 55.

The Figures 9 to 11 still show a creel device intended to feed the knitting yarns by turning them always in the same direction, here that of the needles of the watch ( figure 11 and allowing the knitting yarns to rotate around two respective axes of rotation during the knitting of the pant legs, and then around a single axis when knitting the pants upper.

This creel device comprises vertical bobbin supports 61, each of which carries a spool 62 of knitting yarn 52. Each vertical support 61 rests on a support surface 63 while it is guided upwards by a guide rail 64 This guide rail forms, as illustrated by the figure 11 , two small oval loops included in a large oval buckle. The two small oval loops are intended to guide the bobbin supports 61 during the knitting of the trouser legs, while the large loop is intended to guide them during the knitting of the pants.

Each vertical support 61 comprises a connecting member 65 slidably mounted in a vertical groove 66 ( figure 9 ). A slide 67 integral with guiding pins 67a engaged with guide grooves 67b and actuated by a crank mechanism 82 serves to move the connecting member 65 in this vertical groove 66.

The inner end of this connecting member 65 is shaped to engage selectively with flexible drive members 68, 69, 70 ( figure 9, 10 ), forming three endless loops, like the guide rail 64, passing around wheels 71 pivoted about vertical axes 72, 73, 74, 75. The axis 72 is connected to a geared motor 76 also connected to one of the wheels 42 for guiding and driving the chain 41. This geared motor 76 makes it possible to vary the driving speed of the shaft 72, depending on whether the The supports 61 rotate according to the two small loops of the guide rail 64 or in the large loop, ie they are engaged with the drive members 68, 69 or with the drive member 70.

As in the previous embodiment, the carriages 40 are connected to the drive chains 41 by a servo-control system as illustrated by FIG. figure 8 , making it possible to vary the speed of the carriages relative to that of the drive chains 41.

To explain the operation of this second embodiment, we will start from a carriage 40 moving in the direction of the arrow F ₁ ( figure 12 ) and arriving at the transfer station 55 which is located towards the left end of the needle beds 43, 44. This part of the knitting machine is illustrated in more detail by the figures 13 and 14 which we can refer to. The carriage 40 which moves in the direction of the arrow F ₁ , carrier of the guide wire 46 which drives the knitting yarn 52 is about to arrive at the transfer station 55, while the carriage 40 which moves in the direction of the arrow F ₂ carrying the thread guide 46 empty of knitting yarn also arrives at the transfer station 55.

Arriving at this transfer station 55, the return 49a of the wire guide 46 moving in the direction of the arrow F ₁ meets the rack 56 which rotates the wire retainer 50 in the direction of the arrow F ₃ ( figure 13a ). Practically simultaneously, the portion 51a of the locking member 51 of the knitting yarn 52 ( figures 13 , 14 ) encounters the cam 57 which rotates this locking member 51 against the pulling force of the spring 54, so that the locking member 51 rotates in the direction of the arrow F ₃ ( figure 13a ), releasing the radial notch 50a and thus releasing the knitting yarn 52.

As soon as it is released, the knitting yarn 52 is then moved by the pusher 58b against the abutment surface 55a and the slider 59 closes the space in which the knitting yarn is imprisoned, as shown in dashed lines on the figure 14 . The wire is then positioned to be caught in a radial groove 50a of the wire retainer 50 which is moved in the direction of the arrow F ₂ , as illustrated by FIG. figure 14 . Practically simultaneously, the rack 56 meets the reference 49a which rotates by 90 ° the retaining member 50 of the knitting yarn 52 in the direction of the arrow F ₃ , which is locked by the locking member 51.

The same transfer operation is then performed in the opposite direction when the carriage 40 which moves in the direction of the arrow F ₂ has reached the transfer station 55 'which is located in the middle part of the needle beds 43, 44. The post 55 'does not differ from item 55 of the figure 14 that by the fact that to transfer the knitting yarn 52 of the needle bed 44 to the needle 43 is the slide 59 'with a 59'b arm 90 ° which must pull the wire 52' from right to left instead to push it from left to right as does the 58b pusher of the figure 14 . The rest of the operations are the same so that we can refer to the figure 14 .

Symmetrical operations are performed on the knitting yarns, knitted on the right half of the needle beds 43, 44. When the pant legs or pantyhose are finished and it is necessary to pass to the top of the trousers, the two transfer stations 55, 55 'located in the middle of the needle beds 43, 44 are taken out of service and the transfer of the knitting yarns 52 is made only at the two ends of the needle beds 43, 44.

The reels 62 are moved on the creel following the movement of the wire guides 46 driven by the carriages 40. During the knitting of the trouser legs, the connecting members 65 of the supports 61 of the coils 62 are connected to the flexible drive members 67, respectively 68 and are guided along the two small elongated loops formed by the guide rail 64. When knitting the top of the pants, the connecting members 65 are connected to the flexible drive member 70 by the actuating members 67 and then describe a single elongate path.

In both embodiments described above, each bed is made in one piece. In a variant not shown, one could resort to two-part bedbugs capable of moving laterally relative to each other according to a known system in straight knitting machines. Thanks to this type of needle bed, after having knitted the two tubular parts, it would be possible to join the two parts of the needle bed to knit the common tubular part corresponding to the top of the pants.

Claims (12)

1. Method of forming a seamless knit comprising tubular elements of variable diameter on a linear knitting machine in which the stitches are formed by the descent of knitting needles, comprising two parallel sections (1, 2, 43, 44) for guiding said knitting needles (3), means for selecting these knitting needles (3) in order to increase or reduce the diameter of these tubular elements during knitting, carriages (4, 40) provided with knitting cams for moving the selected knitting needles (3) and members (10, 10') for guiding the knitting thread (52), according to which

   - the sections (1, 2, 43, 44) are placed so that the needles (3) of one section (1, 2; 43, 44) do not cross the needles of the other section during their normal knitting travel;

   - said carriages (4, 40) are moved in a single direction along each section (1, 2, 43, 44), the directions of movement of said carriages (4, 40) along their respective sections being opposite to each other;

   - a knitting thread is delivered by means of a thread guide associated with each carriage, which moves with respect to a succession of selected needles of a section in order to form part of the tubular knit;

   characterized in that

   - the thread is separated from the carriage with which it is associated and transferred, by means of transfer members (14), from the needles (3) of one section (1, 43) to those of the other section (2, 44) each time said thread (52) comes to the end of said succession of needles (3) selected;

   - it is associated with another carriage located at the start of a succession of selected needles of said other section in order to form the other part of said tubular knit;

   - the positions of the transfer members (14) for transferring said thread are changed each time that the diameter of said tubular element or elements increases or decreases; and

   - the speed of movement of the carriages is varied according to the increase or decrease of the knit.
2. Method according to Claim 1, characterized in that first of all, two sets of needles (3) are selected on each section (1, 2, 43, 44), each facing one another, the needles (3) of the two sets of each section being separated from each other by unselected needles, two tubular elements are knitted side by side by transferring the thread (52) from one section (1, 43) to the other (2, 44) each time it arrives at one end of one of said sets of selected needles, then, having reached the desired length for said tubular elements side by side, the needles (3) separating said two sets of needles are selected to join said tubular elements side by side and to form only a single tubular element.
3. Linear knitting machine for implementing the method according to Claim 2, comprising two sections (1, 2, 43, 44) for guiding knitting needles (3) defining needle paths according to which the needles (3) of one section (1, 43) do not cross the needles of the other section (2, 44), means for selecting at least one set of consecutive knitting needles (3) on each section in order to engage them with the drive cams secured to carriages (4, 40), means of guiding (6, 42) and driving (5, 41) these carriages in order to move them in a single direction with respect to said set of needles (3) selected from each section (1, 2, 43, 44), from the start to the end of this set of selected needles and to make them pass from the end of one set of selected needles to the start of the same set or from the other set of selected needles, characterized in that it includes a thread guide (10) suspended from a sliding support (9) engaged with a guide rail (8) and pushers (12, 13) associated with each carriage in order to push said support along said guide rail, cams (21c, 21f, 21e, 21d, 13a) for separating the thread guide from the sliding support (9) driven by the carriage with which it is associated, transfer members (14) for making the knitting thread (52) pass from the needles (3) of one section (1, 43) to those of the other section (2, 44) at the end of each set of selected needles, an adjustment member (20) for adjusting the position of the transfer members (14) according to the diameter of the tubular element or elements knitted, and servomotors (35) for modifying the speed of movement of the carriages (4, 40) relative to said drive means (5, 41) according to the increase or decrease in the knit.
4. Knitting machine according to Claim 3,
   characterized in that said means (6) of guiding said carriages (4) form a closed loop extending in a plane substantially perpendicular to said sections (1, 2).
5. Knitting machine according to Claim 3, characterized in that said means (42) of guiding said carriages (40) form two closed loops in two parallel vertical planes.
6. Knitting machine according to one of Claims 3 to 5, characterized in that said means for making the knitting thread (52) pass from the needles (3) of one section (1, 43) to those of the other section (2, 44) at the end of each set of selected needles comprise thread guides (10) removably connected to slideways (9) engaged with a portion of a guide rail (8) parallel to said sections (1, 2, 43, 44) and members (12, 14) for separating the thread guides (10) from said slideways (9) and for engaging them with slideways (9) located on a portion of said guide rail (8) parallel to the other section.
7. Knitting machine according to one of Claims 3 to 5, characterized in that said means for making the knitting thread (52) pass from the needles (3) of one section (43) to those of the other section (44) at the end of each set of selected needles comprise elements (50) for grasping the knitting thread (52), means (41) of guiding these grasping elements (50), forming two parallel segments, each one running alongside one of said sections (43, 44), means (57) for freeing said knitting thread (52) from said grasping means (50) engaged with said segment running alongside one of said sections (43, 44), means (55) for transferring the freed knitting thread (52) to a grasping element (50) engaged with said parallel segment running alongside the other of said sections (43, 44) and means (49, 49a, 56) for engaging said knitting thread (52) with said grasping element (50) to which it has been transferred.
8. Knitting machine according to one of Claims 3 to 7, characterized in that it comprises means (39) for retaining the knit on each of the sections (1, 2, 43, 44) counter to the movement of the needles (3) with respect to said sections.
9. Knitting machine according to one of Claims 3 to 6 and 8, characterized in that said thread guide (10) comprises at least one ring (10c) of substantially larger diameter than that of the thread guide (10) placed between two annular stops (10d) having diameters greater than that of said ring (10c).
10. Knitting machine according to one of Claims 3 to 9, characterized in that it comprises supports (24, 61) for reels (23, 62) mounted on guide means (25, 64) along closed-loop paths, drive means (M, 76, 68-70) being intended to drive these supports along said paths in synchronization with the movement of said thread guides (10, 46).
11. Knitting machine according to one of Claims 3 to 10, characterized in that each of said carriages (4, 40) is connected to a flexible drive element (5, 41) via means (34, 35, 36) capable of moving the carriages (4, 40) in a direction parallel to said flexible drive element (5, 41).
12. Knitting machine according to one of Claims 3 to 11, characterized in that the thread guide (10') is a tubular element open at both ends, the tubular pipe of which serves to guide the thread (52).

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