FR2913986A1 - Double sided fabric knitting machine e.g. double plate type knitting machine, for textile industry, has unit for pivoting kneader arms with respect to cutting positions at needles between cutting positions on needle boards - Google Patents

Abstract

The machine has needles mounted on needle boards (3, 4), where the needles have lengths (D1, D1') which are different from each other. A pivoting unit pivots asynchronously kneader arms (13, 13') with respect to proper cutting positions at each needle and with respect to similar paths traveled by the needles at a same time between the cutting positions on the boards based on length difference of the needles. A knitting thread conveys a knitting zone (9) in a space located under the paths of the needle (6). An independent claim is also included for a method for knitting double sided fabric.

Description

Knitting device comprising at least one needle bed with needles

  different dimensional characteristics.

Technical Field of the Invention

  The present invention is in the field of the textile industry, and more particularly in the field of knitting devices. It relates to a knitting machine employing hook and pallet needles, which are movably mounted on a needle bed for the manufacture of a mesh fabric, between a slaughter position and a gripping position. a wire.

State of the art

  In the field of textile making, it is traditional to use knitting machines using hook and pallet needles which are mounted movably on at least one bed. The needles are individually movable to move their distal end into an open area of knitting of the machine. In this knitting zone, the needles seize and escape at least one thread so as to form successive meshes constituting the textile. The needles are moved individually and successively in translation on the needle bed, between at least one gripping position of a wire and a felling position in which the mesh is formed while a mesh previously formed is discharged to a collection zone textile. The distal end of the needles is shaped hook to seize one or more son during a movement between two successive felling positions. The proximal end of the needles provides support for maneuvering means needles fitted to the knitting machine. Such maneuvering means are for example of the type implementing a plurality of cams which cause the individual and successive movements of the needles. During a cycle of movement of a needle between two slaughter positions, one or more threads are gripped by the hook and are led to a slaughtering element that includes the bed for the formation of a mesh. This slaughtering element comprises in particular a slaughtering tooth, or similar element such as a slaughter plate or a slaughter hook. A pallet is pivotally articulated at the distal end of the needles to retain the son or son grasped by the hook during the formation of the mesh. The pallet is pivotally movable between an opening position of the needle allowing the hook to be taken up by the hooks, and a position for closing the needle in which the pallet is folded towards the hook to prevent an escape from the hook. or wires. Maneuvering the pallet in the closed position is caused under the effect of the supply of the needle in the felling position, the pallet then abutting against the mesh of the previous row, itself resting on the tooth of slaughter or the like; the operation of the pallet in the open position is caused by a tension exerted by the mesh previously formed during the movement of the needle from the slaughter position to a setting position of yarn. The needles are defined on the basis of their dimensional characteristics, and in particular on the basis of a characteristic of needle length corresponding to the distance separating the hook and the end of the pallet in the open position.

  The organization of the knitting zone must take into account the complexity of the needle kinematics. The complexity of this kinematics is to be apprehended with regard to the mobility of the pallet on the needle, with regard to the individual mobility of the needle on the needle bed, and with regard to the mobility of all the needles successively on the bedding along similar trajectories. This complex kinematics makes narrow access to the knitting zone for feeding the threads seized by the needles. This access is made even more difficult as the yarn supplying the knitting zone can be numerous to give the textile specific characteristics. For example, one or more son of color and / or elastic material may be integrated into the textile to improve its aesthetic appearance and / or flexibility. It is also desirable to provide access to the knitting zone so as to offer the possibility of easily making a textile from various possible knitting modalities, and finally to knit according to an optimized number of mesh structures which are susceptible to knitting. to be complex. Moreover, it is also sought after a machine whose performance is the best possible, by organizing a movement of the needles with high rates.

  The easy access to the knitting zone and the obtaining of high speeds are made all the more delicate to obtain when the knitting machine is double needle. The beds are for example rectilinear type associating two trays opposite constituting the set of a bed, or the circular type associating a tray constituting one of the beds, which overhangs a cylinder constituting the other bed, or the superimposed cylinder type. Such a knitting machine is used in particular for making double-faced technical textiles, such as those used in the field of furniture, decoration and / or upholstery, for example. A double-sided textile associates two outer plies which are independently knitted by the needles of a respective needle bed, and which are interconnected by at least one binding yarn circulating between the stitches of one of the outer plies of the textile. The binding yarn is intended to give the textile its thickness, maintaining a set gap between the two outer layers. The binding thread is seized by the needles mounted on one and the other of the needle beds, and is brought into the slaughter zone together with the son or son that are assigned to these needles. The thickness of the textile is defined by the spacing of at least one of the needle beds with respect to a point of intersection of the corresponding needle paths. Corresponding needles include needles which are arranged substantially opposite a needle bed to another for the formation of a set of meshes given from one to the other of the outer layers of the textile. When this spacing is consistent, such as for the manufacture of a thick fabric, access to the knitting zone for the formation of complex meshes and / or the contribution of a large number of son is facilitated. On the other hand and in view of the aforementioned constraints of the complex kinematics of the needles, such access is particularly difficult in the case of a low or medium thickness textile, indicatively up to 6 mm thick. A known solution to facilitate access to the knitting zone consists in making the corresponding needles work in an asynchronous slaughtering mode. Such asynchronous work makes it possible to avoid cluttering the knitting zone by simultaneous movement of the corresponding needles, and consequently to prevent the pallets of these corresponding needles from being pivotally manipulated simultaneously with the risk of injuring or breaking. son, and allows to regularize the mesh by additional tension of the wire. In order to limit the tensions on the yarns, and in particular on a binding yarn, it is preferred that the knitting machine operate in a synchronous felling mode, according to which the corresponding needles are operated simultaneously. This solution is however implemented at the expense of a preservation of the son, and a faculty offered to optimize their number and / or to allow knitting according to an optimized choice of possible mesh structure and / or following structures of mesh complex, but induces a risk of injury, or even 15 breaks son. This risk is increased due to a supply of yarns in a space of the knitting zone on which are open the hooks of one and the other of the needles to allow the setting of the knitting yarn which is assigned to them, even binding thread.

Object of the invention

  The object of the present invention is to provide a knitting machine comprising at least one needle bed equipped with hook needles and pivoting pallet, which is organized so as to offer high speeds while facilitating the supply of the knitting zone. son, to allow the easy making of a textile with a complex mesh structure and / or incorporating multiple son. It is more particularly the object of the present invention to provide such a double-needle type knitting machine for the manufacture of a double-sided textile that may be of low or medium thickness, as a guide to a textile. up to 6 mm thick, which not only allows to achieve the results just mentioned, but also to preserve the yarns, including the knitting yarn respectively assigned to the needles of one and the other bedbugs.

  The inventive step of the present invention was to maintain high rates of movement of the needles on the needle bed from a synchronous slaughter operation, to reduce tension on the son or son, and in particular on a binding yarn , while making asynchronous the pivoting of the pallets that the needles contain with regard to their individual displacement. Such asynchronous pivoting corresponds to a pivoting of a pallet of a first needle which occurs at a different time on the trajectory of this first needle with respect to the pivoting of the pallet of a second needle with regard to the trajectory of this first needle. second hand. In other words and considering for each of the needles a reference time corresponding for example to the setting in individual position of the needles in the position of slaughter, the pivoting of their respective pallet occurs at a moment of pivoting which is different from the one to the other of the needles with regard to their own moment of reference.

  The asynchronous character of the pivoting of the pallets is obtained from the use of different needles of needle length, the distance separating the hook and the end of the pallet in the open position of a needle being different from the distance analog of at least one other needle. The trajectories of the needles are similar and their individual periods of movement between two slaughtering positions are identical, in order to maintain high speeds from means of maneuvering the needles which are simple and of the type commonly used in the field, such as cam-type operating means or the like.

  In view of the results provided by the present invention, their advantages are particularly useful for application to a double needle bed knitting machine. According to this application and with regard to the inventive step, the complex kinematics of the needles is decomposed, not only potentially with regard to each of the needle beds but especially with regard to the displacement of the corresponding needles from one to the other of the beds. More particularly, the inventive step of the present invention with regard to its application to a double needle needle knitting machine, consisted in dissociating the parameters of the kinematics of the needles, maintaining a synchronous displacement of the corresponding needles and causing asynchronous displacements from the slaughter phase of the pallets from one to the other of the corresponding needles. The asynchrony of the respective pivoting of the pallets of two corresponding needles makes it possible to best disengage the knitting zone despite the synchronous displacement of these corresponding needles. To obtain such a kinematics, it is exploited a difference in needle length between the corresponding needles from one to the other of the needle beds.

  It will be recalled that the corresponding needles are those arranged substantially opposite one needle to the other for the formation of a set of meshes given from one to the other of the outer layers of the textile, and which are displaced simultaneously from one to the other of the bedbugs following similar trajectories for the same duration between two individual slaughter positions. It is also recalled that the needle length corresponds to the distance separating the end of the hook from the end of the pallet to the open position of the needle.

  It follows that the supply of a plurality of son in the knitting zone is simplified, including a double-sided textile of small thickness despite a position close to the needle beds to the crossing zone of the corresponding needles that they support respectively. As the pivoting of the pallets is asynchronous, the feeding of the knit yarns may take place in respective spaces in the knitting zone on which the hook of the needle carried by the other needle never opens. The knitting and feeding conditions of the yarns can be more easily organized, including for the production of complex meshes and / or with the use of a large number of yarns, for high needle movement rates maintained along trajectories. similar and synchronous felling between two corresponding needles, to adjust the spacing of the needle beds from each other to determine the thickness of the textile to be made.

  In the preferred case of using a dual needle type machine cylinder and tray, the shorter needles are carried by the needle bed, this needle bed being likely to be removed from the needle bed tray point of intersection between the respective trajectories of the corresponding needles.

  The association between the use of a shorter needle relative to a corresponding needle, and the operation of said removal of a needle bed carrying this shorter needle, provides a pivoting of the pallet of this needle shorter which intervenes on the back of the other corresponding needle, and consequently the choice of the knitting yarn by the needles of the determined needle bed and in particular the knitting yarn assigned to this other corresponding needle. Despite the synchronous displacement of the corresponding needles from one to the other of the needle beds, the threads are preserved because of the closure of the pallet of the shortest needle which is made on the back of the body of the corresponding other needle . In addition, the shortest needle runs on the back of the longest needle and the hook of the longest needle runs in an area at least partially clear of the presence of the shortest needle.

  Feeding the yarns into the knitting zone in front of the needles is allowed. The tension in the yarns respectively assigned to the constituent plies of the double-sided textile is sufficient to perform the knitting under satisfactory conditions, without compromising the synchronous felling mode corresponding needles and therefore at high rates of knitting, or without the maneuver pallets induce a risk of injury of the son by them. The binding wire can be easily preserved from overvoltages that can be induced by the synchronous felling mode.

  According to a general definition of the present invention, the knitting machine uses at least one needle bed on which are mounted mobile hook and pallet needles. Such needles each consist of an elongate body whose distal end is shaped hook and is provided with a pallet. This pallet is pivotally mounted between a closed position of the needle in which the pallet is folded towards the hook to make prisoner at least one previously grasped thread, and an open position of the needle in which the pallet is folded against the body of the needle to allow the hook to grab a thread. The needles have a needle length which is defined by the distance separating the distal end of the hook from the end of the pallet to the open position of the needle. The needles are movable in translation on the needle bed by operating means between a slaughter position and at least one gripping position of a wire. The slaughtering position corresponds to a position of the needle on the needle bed that carries it, according to which at least one wire grasped by the hook of the needle is introduced through a mesh previously formed, and according to which an anterior mesh is clear of the needle to a textile collection area. The gripping position of the thread corresponds to a position of the needle on the needle bed which carries it according to which the needle hooks a thread in a knitting zone of the machine, to which the threads are fed by guide means in order to from their grip by the needles. The maneuvering means are, for a given needle bed, of the type successively causing the displacement of the needles following felling trajectories, or portions of trajectory, and similar durations.

  In general, a knitting machine of the present invention will be recognized in that the needles have needle lengths which are different from each other by at least two needles, this difference in length of the needle constituting pallet asynchronous pivoting means with regard to the setting in the felling position specific to each needle and in view of similar felling paths traveled by the needles at the same time given between two individual felling positions on the needle bed which the door.

  The means for maneuvering the needles are advantageously of the common commercial type, such as a cam track or the like, causing a successive displacement of the needles supported by a needle bed along similar trajectories and durations from one to the other. needles. Such arrangements are provided to allow knitting with high rates of formation of each of the rows of mesh of the resulting textile, from structurally simple maneuvering means. Despite such a structure of the maneuvering means and thanks to said difference in needle length, the pallets from one to the other of the needles are not maneuvered at the same time with respect to a reference time specific to each needle. At the same instant or even duration, we shall understand moments or durations which have the same value, whether they are simultaneous or not.

  As an indication, the amount of needle length difference is between 1.1 and 1.5 times the needle length of one needle relative to the needle length of the other needle.

  Preferably, the difference in needle length is constant between any two needles taken two by two to maintain the operation of structurally simple maneuvering means. However, it can be envisaged that such a difference in needle length is variable between needles carried by the same needle bed, or even for groups of corresponding needles of different lengths carried by respective needle beds of a double needle machine. . The invention is applicable for a single needle knitting machine, in which the needles of different needle lengths are needles carried by the same needle bed.

  However, the advantages of the present invention are of particular interest for a double needle machine, in which the needles of different needle lengths are the corresponding needles carried by a respective needle bed of a double needle type machine. . These arrangements are likely to be taken in combination with a difference in needle lengths between needles worn by the same needle bed of this machine double needle.

  More particularly, the means for maneuvering the needles in the slaughter phase cause a synchronous displacement following similar felling trajectories of two needles corresponding to each other of the needle beds. The means of maneuver provoke on the same needle successively the displacement of the needles along similar trajectories and durations, and cause from one to the other of the needle beds a displacement of the corresponding needles so that they intersect, the trajectories and durations of these displacements being not only similar, but also occurring simultaneously.

  Such a double needle machine is indifferently either a needle-type machine with needle bed and needle bed, or a machine of the double-tray type, or a machine of the double cylinder type, or other similar knitting machine with a double needle.

  Since the double needle machine is a machine of the needle-bed and needle-bed type, the shorter needles are preferably carried by the needle-bed while the longer needles are carried by the bed-plate, to enable the case where appropriate. to associate the provisions relating to the difference in length of needles between two corresponding needles, with a possible difference in separation distance between respective needle beds and the crossing point of the corresponding needle paths.

  More specifically, the machine may have means for adjusting the separation distance between the cutting tooth of at least one of the needle beds, and more particularly, if appropriate, of the needle bed, with respect to a point crossing the trajectories of the corresponding needles. These adjustment means make it possible to vary this separation distance as a function of the thickness of the textile to be obtained. In this case, the shorter needle of the same pair of corresponding needles is advantageously carried by the needle bed whose felling tooth is furthest from the crossover point, and more particularly if necessary by the needle bed .

  In other words more general, the machine is equipped with means for adjusting the separation distance between the felling tooth of the needle bed supporting the shorter needles and the crossing point of the respective paths of the corresponding needles, is greater at the separation distance between the slaughtering tooth of the needle bed supporting the longer needles and said crossing point.

  The present invention will also be recognized by a knitting process using the proposed dual needle bed machine consisting in moving corresponding needles from one to the other of the synchronously sloping needle beds in similar trajectories, and causing the maneuvering respective pallets to these corresponding needles asynchronously from the use of needles of different needle lengths from one to the other of these corresponding needles.

  Continuing the process, the method also more particularly involves causing the pivoting of the pallet in the closed position of the shortest needle in an area located at the back of the body of the longest needle, from a choice of relative length of the shortest needle not only with respect to the longest needle but also with respect to the difference between said separation distances of the felling teeth from the corresponding needle crossover point .

Description of the figures.

  The present invention will be better understood, and details will arise from reading the description that will be made of a preferred embodiment in connection with the figures of the attached plates, in which fig.1 to fig.8 are diagrams illustrating corresponding needles of a double needle needle knitting machine according to an exemplary embodiment of the present invention, according to different successive positions of the needles between two slaughter positions.

  In the figures, a knitting machine is double needle for the manufacture of a double-sided textile. This textile comprises two outer plies 1,2 which are knitted by a set of respective needle beds 3,4 and which are interconnected by a binding yarn 5. In the illustrated embodiment, the knitting machine is of the type comprising a first bedding arranged in needle bed 3 which is arranged overhanging a second bedding arranged in needle bed 4.

  Each of these needle beds 3.4 movably carries in translation groups of needles, which are substantially placed opposite each other in pairs during operation of the machine. In the figures, only a needle 6.7 is shown for each of the needle beds, these needles 6,7 being corresponding needles placed substantially facing one another, so that their trajectories are concurrent at a crossing point 8 located in a knitting zone 9 of the machine to which are conveyed son. In the exemplary embodiment illustrated, one can distinguish the needle plate 6 carried by the bed plate 3 and the cylinder needle 7 carried by the cylinder needle bed 4. Furthermore, in the illustrated embodiment the son include the wire of binding 5 and a pair of knit yarns 10, 11 respectively assigned to the formation of knits specific to each of the plies 1,2. However, it will be understood that the use of only three son 5, 10, 11 is illustrated for example, and an interest of the present invention is to best free the knitting zone 9 for the routing of son in a substantial number and / or for the formation of a mesh fabric of complex structure, while preserving these son and maintaining high rates of movement of the needles. It will also be understood that the assignments to a first needle of a bedbug arrangement 3 and a second bed of a needle bed arrangement 4 are defined to illustrate the advantages of the present invention.

  The needles 6,7 are 12.12 'hook type and pallet 13,13' formed at the distal end of a body 14,14 'guided inside a corridor that includes the bed 3.4 corresponding. The pallet 13, 13 'is pivotally mounted on the body 14, 14' to be operable between a closed position of the needle 6, 7 as shown in FIG. 1, and an open position of the needle 6, 7. as shown in fig.3. The passage of the pallet 13,13 'from an open position of the needle 6,7 to a closed position is caused during the displacement of the needle 6,7 in translation towards its position of setting wire and then cutting. During this movement, the mesh 15 previously formed and resting on the felling tooth 3 ', 4' maneuver the pallet, as shown in fig.5. The reverse passage of the pallet 13,13 'from the closed position of the needle 6,7 to the open position of the needle 6,7 is caused when the needle 6,7 is moved towards a setting position. a wire 5, 10, 11, under the effect of the traction exerted by the mesh 15 previously formed, as represented in FIG. Needles 6, 7 of the hook type 12, 12 'and pallet 13, 13' are commonly defined according to a dimensional characteristic of needle length D1, D1 ', corresponding to the separation distance between the end of the pallet 13, 13 in the open position of the needle 6,7, and the distal end of the hook 12,12 'or in other words the body 14,14'. The needles 6,7 are movable in translation on their respective needle bed 3,4, between a slaughter position shown in Fig.8, and various tap positions of a wire as shown in Fig.3 to Figs. 6.

  The maneuvering means equipping the machine are not shown, these operating means being capable of being arbitrary and in particular being operating means usually used for such knitting machines. Maneuvering the corresponding needles 6,7 is synchronized, that is to say that their displacement on their respective needle bed 3,4 between two successive slaughter positions is carried out according to the same duration and in the case of example illustrated in FIG. the same time. It will be understood that the displacement of the needles 6, 7 are only for the same duration but at the same time corresponding to the specific application illustrated of the present invention to the corresponding needles 6,7 of a machine double needle 3,4 .

  To adjust the thickness of the textile, the needle bed 4 is mounted axially movably on the machine so as to adjust the separation distance D2 'between the cutting tooth 4' of the needle bed 4 with respect to the crossing point 8 needles 6,7. These provisions are more precisely to adjust the separation distance between the cutting teeth 3 ', 4' of the two needle beds 3,4, and consequently to adjust the separation distance between the two outer plies 1,2 knitted.

  The needles 6,7 corresponding are needle lengths Dl, Dl 'different from one to the other of the needle beds 3,4. The needle 7 of the shortest needle length is preferably disposed on the needle bed 4, so that the operation of its pallet 13 'in the needle closing position occurs earlier than the similar maneuver of the pallet 13 the other corresponding needle 6 carried by the plateau bed 3, as shown in Fig.5 and Fig.6, and this although the machine operates in synchronous felling mode. In addition, the needle lengths and in particular the difference in needle length between the corresponding needles 6,7 are chosen as a function of the separation distance D2 'of the felling tooth 4' of the second needle bed 4 relative to at the point of crossing 8 needles 6,7. This choice is such that the pivoting of the pallet 13 'of the needle 7 carried by the cylinder needle 4 towards its closed position takes place on the back of the corresponding other needle 6 carried by the bedding plate 3. This pivoting is more particularly in an area between the felling tooth 4 'of the needle bed 4 and the crossing point 8 of the trajectories of the needles 6,7, as illustrated in FIG. Note that the choice to place the shortest needle 7 on the cylinder needle 4, although subsidiary, if necessary depending on the setting of the distance D2 'separation between the felling tooth 4' of the needle bed cylinder 4 and the crossover point 8 to easily exploit such an arrangement to minimize the risk of interference between the knit thread 10 assigned to the needles 6 of the bed needle 3 and the pallet 13 'of the needle 7 worn by the needle cylinder 4 during its maneuver.

  In Fig.8, the two needles 6.7 are in the slaughter position. In Fig.1, an old mesh 16 is pushed to a collection area 17 of the textile, and the needles 6.7 are moved simultaneously in translation to a yarn setting position. In FIG. 2, the displacement of the needles 6,7 causes the opening of their pallet 13, 13 'under the effect of a traction exerted by the previously formed mesh 15. It will be noted that the operation of the pallet 13' the needle 7 carried by the needle bed 4 intervenes on the back of the needle 6 carried by the plateau bed 3. In Fig.3, the needles 6.7 are simultaneously placed at the end of the race along their respective paths which are similar. The binding yarn 5 is shown. In Fig.4, the needles 6.7 are simultaneously operated to their slaughter position, and the needle 7 carried by the needle bed 4 grasps the binding yarn 5. In Fig.5, the binding yarn 5 is crocheted by the needle 7 carried by the cylinder needle bed 4, which then seizes the knit yarn 11 which is assigned to it. It will be noted that this knit yarn 11 is brought into the knitting zone 9 in an open space located under the trajectory of the needle 6 carried by the bed-plate 3. The pallet 13 'of the needle 7 carried by the needle bed 4 is manipulated by the mesh 15 previously formed and placed in abutment against the felling tooth 4 ', to engage the closing of the needle 7 which ends after the seizure of the knit yarn 11 by the hook 12' of the 7. During this time, the needle 6 carried by the tray needle grips the knit thread 10 which is assigned to it. It will be noted that the feeding of this knit yarn 10 is carried out in an area outside which the pallet 13 'of the needle 7 carried by the needle bed 4 is maneuvered, so that it is protected from any risk of injury. interference and that its supply is facilitated because of the clearance of this zone. In Fig.6, the needle 7 carried by the needle bed 4 is closed while the pallet 13 of the needle 6 carried by the bed-plate is brought to the slaughter tooth 3 'to engage the closure of this needle 6. The binding thread 5 is gripped by the needle 6 carried by the bed needle 3 before the completion of the closure of the needle 6. In Fig.7, the needles 6,7 are closed and moved to their position. respective felling position shown in fig.8.

Claims (10)

claims   1.- Textile knitting machine using at least one needle bed (3, 4) on which are mounted movable needles (6, 7) with a hook (12, 12 ') and a pallet (13, 13'), these needles (6,7) being each constituted by an elongate body (14, 14 ') whose distal end is shaped like a hook (12, 12') and is provided with a pallet (13, 13 '), this pallet (13, 13 ') being pivotally mounted between a closed position of the needle (6, 7) in which the pallet (13, 13') is folded towards the hook (12, 12 ') to make at least one prisoner wire (5, 10, 11) previously grasped, and an open position of the needle (6, 7) in which the pallet (13, 13 ') is folded against the body (14, 14') of the needle ( 6,7) to allow the hook (12,12 ') to grip a thread (5,10,11), the needles (6,7) having a needle length (D1, D1') which is defined by the distance separating the distal end of the hook (12,12 ') from the tip of the pallet (13,13') to the open position of the needle (6 7), the needles (6, 7) being displaceable in translation on the needle bed (3, 4) by means of maneuvering between a slaughtering position in which at least one wire (5, 10, 11) grasped by the hook (12,12 ') of the needle (6,7) is introduced through a mesh (15) previously formed and in which an anterior mesh is released from the needle (6,7) towards a collection zone (6,7). 17) of the textile, and at least one gripping position of a yarn (5, 10, 11) in a knitting zone (9) of the machine to which the yarns (5, 10, 11) are fed by means for guiding the needles (6,7), the operating means being, for a given needle bed (3,4), of the type successively causing the displacement of the needles (6,7) along trajectories slaughter and similar durations, characterized in that the needles (6,7) have needle lengths (D1, D1 ') which are different from one another at least two needles (6,7). ), this diff needle length erection (D1, D1 ') constituting means for asynchronous pivoting of the pallets (13, 13') with respect to the setting in the felling position specific to each hand (6, 7) and with respect to trajectories similar traveled by the needles (6,7) at the same time given between two individual positions of slaughter on the needle bed (3,4) which carries them. 17   2.- knitting machine according to claim 1, characterized in that the proportion of difference in needle length (D1, D1 ') is between 1.1 and 1.5 times the needle length (D1, D1 ') of one needle with respect to the needle length (D1, D1') of the other needle.   3.- knitting machine according to any one of the preceding claims, characterized in that the needles of different needle lengths are needles carried by the same needle bed.   4.- knitting machine according to any one of the preceding claims, characterized in that the needles (6,7) of different needle lengths are the needles (6,7) corresponding carried by a needle bed (3,4) respective of a double needle type machine.   5.- knitting machine according to claim 4, characterized in that the double needle needle knitting machine is indifferently either a cylinder needle type machine (4) and needle bed (4), or a machine type double tray, or a double cylinder machine. 20   6.- knitting machine according to any one of claims 4 and 5, characterized in that the means of maneuvering the needles (6,7) cause in slaughter phase a synchronous movement along similar paths of two needles (6). 7) corresponding from one to the other of the needle beds (3, 4).   7.- knitting machine according to any one of claims 5 and 6, characterized in that the double needle machine being a cylinder needle type machine (4) and needle bed (3), the needles (7) the more than 30 short are carried by the needle bed (4) while the longest needles (6) are carried by the needle bed (3). 10 15   8.- knitting machine according to any one of claims 4 to 7, characterized in that it is equipped with means for adjusting the distance (D2 ') of separation between the felling tooth (4') of the the needle (4) supporting the shorter needles (6, 7) and the crossing point (8) of the respective trajectories of the corresponding needles (6, 7) is greater than the separation distance (D 2) between the tooth of slaughtering (3 ') of the needle bed (3) supporting the longer needles (6, 7) and said crossing point (8).   9. A method of implementing a knitting machine according to any one of claims 4 to 8, characterized in that it consists in moving corresponding needles (6,7) from one to the other beds (3,4) in synchronous felling according to similar trajectories, and to cause the palettes (13,13 ') respectively to be operated at these corresponding needles (6,7) asynchronously from the use of needles (6,7) needle lengths (D1, D1 ') different from one to the other of these needles (6,7) corresponding.   10.- Method according to claim 9 for the implementation of a knitting machine according to claims 7 and 8, characterized in that it consists in causing the pivoting of the pallet (13 ') in the closed position of the needle (7) the shortest in a zone located on the back of the body (14) of the needle (6) the longest, from a choice of relative length of the needle (7) the shortest no only with respect to the longer needle (6) but also with respect to the difference between said separation distances (D2, D2 ') of the felling teeth (3', 4 ') with respect to the crossing point (8) corresponding needles (6,7).