CA2677476A1

CA2677476A1 - Needle motion

Info

Publication number: CA2677476A1
Application number: CA002677476A
Authority: CA
Inventors: Jan Ando
Original assignee: Individual
Current assignee: Golden Lady Co SpA
Priority date: 2007-02-12
Filing date: 2008-02-07
Publication date: 2008-08-21
Also published as: KR20090110893A; CZ2007107A3; RU2009134123A; WO2008099436A1; JP2010518274A; BRPI0807460A2; WO2008099436A8; US20100095709A1; EP2126175A1; MX2009008591A

Abstract

A needle motion with a knitting needle having formed, on both its ends of the stem (2), a knitting spring hook or beard (3, 4) extended by an elastic buckle (5, 6). The needle motion makes it possible to produce seamless knitted goods of the type of underwear, it simplifies the construction of the knitting machines and it improves the cost-effectiveness of the production by means of reduction of the duration of the production cycle.

Description

NEEDLE MOTION
Background of the invention The present invention relates to a needle motion for a double-bed knitting machine, such as a double-cylinder circular knitting machine, two-needle bed or four-needle bed flat knitting machines, or similar machines, designed in particular for an automated production of seamless knitted outerwear and underwear of the tubular type, for example trousers, panties, leggings, undershirts, T-shirts, pull-overs, and the 'like, with a possibility of a reversible and a links-links structure of the knitted fabric in the rib-top area.
The invention further concerns a knitting machine as well as a knitting needle.
Description of the prior art A highly and fully automated production is an essential requirement for every modern production process. In the case of the products made of the knitted fabric, the field of textile production is, as a rule, characterized by requirements for a large extent of the finishing operations realised by sewing, which is, above all, case of the underwear. This introduces not only a considerable amount of a manual work on the finished product and an increase in the production costs, but also certain devaluation of the manufacture qualities of the knitted fabric in the seam area. Seamless knitted underwear with elastic rib tops in a reversible structure (wale) does not yet exist in practice, although such underwear seems to be an ideal one in terms of utility value.
Knitting machines are known designed for an automated production of knitted goods, in which three tubes are being interconnected. This is for example the case of trousers, panties, leggings, undershirts, T-shirts, pull-overs, and the like. A very important property of these types of knitting machines is among others a capability of realising the knitted fabric, above all in the area of waist opening and leg openings, in the reversible structure (so called wale) in order to prevent the known and undesirable twisting of jersey knitted fabric. , One of these knitting machines is the two-needle bed flat knitting machine with the needle beds arranged in the form of "V". These knitting machines, for making loops, make use of knitting needles with actuation pistons, by virtue of which a transfer of the loops of the knitted fabric to the opposite needle bed is made possible. The main drawback of these knitting machines is that it is necessary, when knitting a tube in a reversible or a links-links structure of the knitted fabric, to establish the purl loop in the first instance on the opposite needle bed and then to transfer it to the needle bed on which the jersey loops of the same course of the knitted fabric are being established.
This leads not only to an inadequate lengthening of the production cycle, but also a constructional complexity which results in that it is possible, on these knitting machines, to make knitted goods in the reversible structure, or eventually in the links-links structure, up to only 9(E) pitch of the knitted fabric, which is, in case of underwear, absolutely insufficient. The type of the needle motion being the source of the above-mentioned drawbacks.
Another known type of the knitting machines intended for the mentioned knitted goods is the four-needle bed flat knitting machine with the knitting needle beds arranged in the form of "X", with a needle motion that is basically identical as the needle motion of two-needle bed knitting machines with the needle beds arranged in the form of "V". An advantage of these types of four-needle bed flat knitting machines in comparison with the two-needle bed knitting machines with the needle beds arranged in the form of "V" rests in the possibility of producing knitted goods up to the 18(E) pitch of the knitted fabric.
For the underwear such as panties, T-shirts, or similar, this is, however, still insufficient. Moreover, it is obvious that the four-needle bed flat knitting machines are mechanically practically twice as complicated as the two-needle bed flat knitting machines. As regards the duration of the production cycle, the four-needle bed flat knitting machines are equally unfavourable as the two-needle bed knitting machines, as the time needed for the transfer of the purl loops onto the opposite needles represents an operating delay.
Another type of knitting machines of the mentioned category are also the four-needle bed flat knitting machines with the knitting needle beds arranged in the form of "X", but making use of double hook needles known from double-cylinder small diameter knitting machines. A great advantage of this category of machines is the fact that the manufacturing technology of the double hook needles was mastered up to the thickness of the needle stem of 0.4 mm, what makes it possible to construct the knitting machines up to the 24(E) pitch.
This significantly broadens the range of the knitted goods that might be made on these knitting machines. However, the complexity of the flat knitting machines of this category is exceptional. Besides the mechanisms for actuation of the double head knitting needles, it is another additional auxiliary special mechanism what is necessary for ensuring the transfer of the purl loop from the hook for making the purl loops to the hook for making the jersey loops at the moment of switching the knitting needle from the needle bed for making the purl loops to the needle bed in which the jersey loops are being made. Another drawback being also a significantly restricted range of the density of the knitted fabric in order to be able to transfer safely the purl loop into the hook for making the jersey loops.
Double-cylinder knitting machines of the state of the art using double-head latch needles are known inter alia from US-A-2003/0101775, US-B-6,220,061, US-A-5,718,128; US-A-4,879,884.
Summary of the invention According to one aspect the invention provides improvements to the current state of the art by providing a new needle as well as a new needle motion enabling designing of knitting machines for making different types of tubular seamless knitted goods in a links-links or a reversible structure in a fully automated production cycle without any considerable restrictions of the pitch of the knitted fabric. According to some embodiments, the goal of the invention is also to enable a simplification of the constructional arrangement of the knitting machine and to no small extent also improving the cost-effectiveness of the production of the mentioned category of the knitted goods by removing the finishing operations realised by sewing and by reduction of the idle time in the production cycle.
These goals are achieved by means of a needle motion according to the invention, the substance of which rests in that the needle motion comprises knitting needles having a double knitting spring beard, i.e. a so-called spring beard or spring hook at each end of a stem, the knitting hook or beard at each end of the stem forming an elastic buckle terminating at a tip, whereas on the stem, in the vicinity of the tips of each elastic buckle of the hook or beard, there are provided corresponding curved portions with a convexity facing towards the respective tip. Said curved portions are provided with respective recesses for the tip of the elastic buckle or beard, and with respective recesses for the projection of a slider or transfer jack used as an actuation element to move the needle. According the invention, therefore, the knitting needle is a so-called spring-beard needle or bearded needle, which is characteristically provided with a double head, i.e. with a beard or spring at both ends of the needle stem.
A main advantage of the needle motion according to the invention in comparison with the devices known from the state of the art and using a double hook knitting needle, i.e. a double latch needle, is that at the switching of the knitting needle from one needle bed to another in case of a flat knitting machine, or from one needle cylinder to another needle cylinder in case of a circular knitting machine, respectively, no automatic knock-over of the loop of the knitted fabric situated on the stem of the knitting needle takes place, in such a manner as it is in case of the known double hook needle. Therefore, the knitting machine does not need a special mechanism for hindering the knock-over of the loop at the time when the knitting needle switches from one needle bed to the other needle bed of the knitting machine without forming a new loop.
On the one hand this considerably simplifies the construction of the knitting machine, and on the other it also considerably speeds up the production cycle, because the operation such as for example establishing of a loop and a subsequent switching of the knitting needle without forming a new loop can simply be carried out by a single working motion of the carriage of the knitting cam system. The advantages of the needle motion according to the invention are even more significant in comparison with the knitting needles with actuation pistons, because, by means of knitting needles with actuation pistons, it is not possible to provide for a knitting machine having such a mechanical delicacy as in the case of the needle motion according to the invention.
According to some preferred embodiments, every knitting needle is provided with a pair of actuation sliders, one slider being arranged in each needle bed. On each of the actuation sliders are arranged at least a bearing surface for the hook of the knitting needle and a projection for hitching the stem of the knitting needle at the recess provided at the level of the above mentioned curved portion of the needle stem. In some embodiments, each slider includes a bevel or nose for realisation of a spontaneous deviation of the actuation slider, a pivot point for deviation of the slider, at least one rigid butt for controlling an axial translation of the slider. According to some preferred embodiments, each slider is also provided with a butt for controlling an oscillatory deviation of the actuation slider, which is of advantage in the case if no links-links patterns are needed to be made in the knitted fabric, for reasons of mechanical simplicity.
In some embodiments, the actuation sliders are provided with an an auxiliary actuation slider with a working butt, said auxiliary actuation slider being swingingly attached to the actuation slider by means of a joint. In such embodiment, when it is necessary to realise a plurality of independent working paths for a rigid working butt of the actuation slider, it is possible to easily achieve a transfer between the respective working paths for the rigid butt by means of a butt on the auxiliary actuation slider.
If both of the pair of the actuation sliders are of the same type, such an embodiment is advantageous in the case when it is necessary to realise identical or similar working paths of the knitting needles in both needle beds or needle cylinders.
If each of the pair of the actuation sliders is of a different type, this is advantageous especially in the case when in one of the needle beds, or in one of the needle cylinders, it is sufficient to realise simplified working paths of the knitting needles.
For making links-links and cardigan patterns in the knitted fabric, it is of advantage if a patterning device is assigned to always at least one of both actuation sliders.
An application of the needle motion according to the invention on the two-needle bed flat knitting machine is of advantage above all thanks to the possibility of achieving a high level of the pitch of the gauge (up to 34 E).
An application of the needle motion according to the invention on the four-needle bed knitting machine is of advantage above all thanks to an overall simplification of the construction of the machine, as the switching of the knitting needles from needle bed to needle bed is substantially simplified in the case when a simultaneous establishing of the loop is not required. It further brings a considerable time saving in the working cycle of the machine, because for establishing of a loop and a subsequent switching of the knitting needle from needle bed to needle bed without forming a new loop the same motion of the carriage of the knitting cam system can be used.
An application of the needle motion according to the invention on the -6-.
double-cylinder small diameter or large diameter knitting machine is of advantage above all thanks to the fact that no mutually synchronized motion of the actuation sliders in the upper and lower needle cylinder is necessary, and that the patterning possibilities of the knitting machine are broadened in comparison with the double hook needle.
According to a further aspect, the invention provides a knitting machine including at least two needle beds, a plurality of knitting needles and corresponding actuating sliders in each needle bed, for controlling knitting movements and transfer movements of said needles from one needle bed to the other, wherein each needle includes a stem and two knitting needle heads (3, 4) arranged at opposed ends of said stem; wherein:
- each needle head includes a spring hook terminating at a tip;
- the stem of said needles is provided with a pair of curved stem portions, each curved portion being arranged in the vicinity of a corresponding one of said tips, said curved stem portions having a convexity facing towards the respective tip;
- each curved stem portion is provided with a first recess) for the respective tip and with a second recess for engagement by a projection of said actuating sliders.
According to still a further aspect, the invention provides a knitting needle including a stem and two knitting needle heads arranged at opposed ends of said stem wherein: each needle head includes a spring hook terminating at a tip; the stem of said needle is provided with a pair of curved stem portions, each curved portion being arranged in the vicinity of a corresponding one of said tips, said curved stem portions having a convexity facing towards the respective tip;
and each curved stem portion is provided with a first recess for the respective tip and with a second recess for engagement by an actuation slider.
Brief description of the drawings The invention will now be described and explained with the aid of following drawings. In the drawings:
Figs. 1 and 1 a show a front view and a side view respectively of a double head knitting needle, i.e. a double-head bearded (or spring beard) needle according to the invention, with hooks provided at both ends of a central stem;
Figs.1 b and 1 c show enlargements of details of Figs. 1 and 1 a;

Fig. 2 shows a side view of the complete needle motion in its simplified variant;
Fig. 3 shows a part of the simplified variant with an actuation slider in an enlarged scale;
Fig. 4 shows one of the possible variants of the actuation sliders allowing making of links-links or reversible and cardigan patterns;
Figs. 5a - 5e show the steps of the exemplary realisation of a jersey loop;
Figs. 6a - 6e show the steps of switching the knitting needle from one needle bed to another without forming a new loop;
Figs.7a-7e show enlarged details of Figs.5a-5e; and Figs. 8a-8e show enlarged details of Figs. 6a-6e.
Detailed description of embodiments of the invention Figure 1 shows a knitting needle according to the invention, which can be used in the needle motion according to the invention. The knitting needle 1 includes a stem 2 having opposedly arranged knitting heads, each including a respective knitting hook or beard 3, 4. Each hook or beard is shaped essentially in a fashion similar to known so-called "spring beard needles" or "bearded needles" or simply "spring needies". Each hook or beard extends therefore forming an elastic buckle or spring buckle 5, 6 terminating at a tip 7, 8. The hook 1 is therefore a so-called "spring beard needle" or "bearded needle", which however, contrary to the bearded needles of the prior art, is double, i.e. is provided with hooks at both ends of the stem. The needle can be formed of one piece of spring steel forming the stem 2 and the two long terminal hooks or beards 3, 4.
On the stem 2 of the knitting needle 1, reaching the position reached by each tip 7, 8 of the elastic buckles 5, 6 when the book is closed by elastic deformation thereof, curved stem portions 9, 10 are provided. Each said curved portion has a convexity facing the tip of the corresponding spring hook. In each curved portion 9, 10 of the stem 2there are arranged recesses 11, 12 or slits into which the tips 7, 8 of the elastic buckles 5, 6 of the knitting hooks 3, 4 can penetrate. Further recesses 13, 14 are also provided in said curved portions, for engagement by projections 17, 25 of corresponding actuation sliders 15, 23.
The knitting needle 1 is therefore symmetrical with respect to its transversal axis X-X.

The needle motion generally comprises a knitting needle 1, and for each knitting needle 1 at least a pair of actuation sliders 15, 23, which may be identical or of a different construction. Figure 3 shows one type of these possible constructions. An actuation slider 15, shown in figure 3 in a larger scale than in figure 2, has a bearing surface 16 for the adjacent hook 3, 4 of the knitting needle 1 and a projection 17 for locking into the respective recess 13, 14 in the curved portion 9, 10 of the knitting needle 1. The actuation slider 15 is further provided with a butt 19 for generating an axial translation, i.e. a sliding movement of the slider and along a sliding recess provided in the needle bed of the knitting machine. The butt 19 engages into cam profiles provided along or around the needle bed in a well known manner and not disclosed. Furthermore the slider 15 is provided with a pivot point 20 for enabling deviation, i.e.
an oscillation motion of the slider around an axis extending orthogonal to the slider and positioned at pivot point 20. A further butt 21 is also provided on the slider 15 for exercising a forced deviation of the slider, i.e. to control the oscillation thereof around the pivot point 20.
With every knitting needle 1 in the needle motion there are associated two actuation sliders 15 as shown in the embodiment illustrated in figure 2, or in another type of realisation two actuation sliders 23 as shown in figure 4. In some embodiments, it is possible to use for the same needle 1 a pair of actuation sliders 15, 23, i.e. different from one another and made according to figures 3 and 4.
According to figure 4, in the alternative embodiment the slider 23 has a bearing surface 16 for the hook 3, 4 of the knitting needle 1 anda projection for hitching into the recess 13, 14 in the curved portion 9, 10 of the knitting needle 1. It is further provided with a rigid butt 19 for controlling 'the axial translation motions of the slider, and with a pivot point 20 for enabling deviation, i.e. an oscillation in the sliding groove of the needle bed, wherein the slider is slidingly housed.
The actuation slider 23 is further provided with a projection forming a joint 29 for a hinged bearing of an auxiliary swinging slider 30, which is shown in working position in solid lines as well as in off-position in broken lines (shown at 31). The auxiliary swinging slider 30 is provided with a seat 35 for the joint such that the two sliders 23 and 30 can be stingingly connected to one another.

The swinging slider 30 is further provided with a butt 32 designed for controlling the oscillatory deviation motion and a butt 33 designed for controlling an axial translation motion. Due to the fact that the butt 33 is individually selectable from a working position to an off-position and vice versa, the swinging slider 30 is predetermined not only for making basic structures, but also for different cardigan and links-links patterns. The swinging slider 30 is actuable by means of any patterning device that is known and therefore not shown in more detail.
The basic function of the needle motion, that is making the loops of the knitted fabric, is shown on the series of figures 5a - 5e, and is common to flat knitting machines and double-cylinder knitting machines. Reference numbers 40 and 41 generically designate two needle beds, which can be either flat needle beds or circular needle beds (needle cylinders of a double-cylinder knitting machine). Figures 7a-7e show enlargements of the needle head in the various positions shown in Figs. 5a-5e.
Figures 5a and 7a show an initial position of the needle motion. The knitting needle 1 is hitched into one of the actuation sliders 15 and is situated in a weft position according to the figure 5a in the right knitting needle bed 40.
In the hook 3 of the knitting needle 1, there is situated for example a jersey loop of the knitted fabric 36. The second, the opposite one, of the pair of actuation sliders 15 is situated in the left knitting needle bed 41, and during the whole stage of forming the new jersey loop is practically out of function. As shown in figures 5b and 7b, the hitched actuation slider 15 with the knitting needle 1 are moved in the direction towards the knitting needle bed 41 to such a position that the loop of the knitted fabric 36 has moved over the curved convex portion 9 of the knitting needle 1. By means of the thread guide that is known and not shown in figures 5b and 7b, the knitting thread 38 is laid into the space between the convex curved portion 9 and the tip 7 of the elastic buckle of the knitting hook 3 of the knitting needle 1. In the next stage, shown in figures 5c and 7c, a backward movement of the slider 15 and the knitting needle 1 is realised in such a way that the knitting thread 38 gets under the elastic buckle 5, but the loop of the knitted fabric 36 that is positioned on the stem of the knitting needle 1 remains behind the curved portion 9. Subsequently, as shown in figures 5d and 7d, a known presser 39 compresses the elastic buckle 5 in such a way that the tip 7 of the elastic buckle 5 gets into the recesses or slit 11 provided the curved convex portion 9 of the knitting needle 1. This makes it possible for the loop of the knitted fabric 36 that is positioned on the stem 2 of the knitting needle 1, by a gradual motion in direction towards the weft position in the knitting needle bed 40, firstly to be put on the elastic buckle 5 and subsequently to fall over the knitting hook 3 and to establish a new jersey loop 37 of the knitting thread 38. The final position of the needle motion is shown in figures 5e and 7e. This position is practically identical with the initial position shown in figure 5a.
Another important feature of the needle motion is the possibility of transferring the knitting needle 1 from one needle bed to another without forming a new loop thereat. This process is shown in the series of figures 6a -6e and in the enlarged details of figures 8a-8e, each showing an enlargement of the needle area of figures 6a-6e respectively. An initial position of the needle motion is shown in figures 6a and 8a. This position of the needle motion is the same as the position shown in figures 5e and 7e. The initial step of the process of transferring the knitting needle is shown in figures 6b and 8b. The actuation slider 15 with the hitched knitting needle 1, that are situated in the right-hand knitting needle bed 40, gradually translate in the direction towards the left-hand knitting needle bed 41, whereas the knitted fabric 36, originally situated in the knitting hook 3, is moved onto the stem 2 of the knitting needle 1.
The actuation slider 15 that is situated in the left-hand knitting needle bed 41 is also in movement and gradually translates towards the knitting needle 1.
At the moment in which the bevel 18 of the actuation slider 15 touches the hook 3 of the knitting needle 1, a gradual and spontaneous oscillatory deviation of the actuation slider 15 around the pivot point 20 on the needle bed 41 begins.
Subsequently, the knitting needle 1 hitches both actuation sliders 15. This position is shown in figures 6c and 8c. After hitching the knitting needle 1 into both actuation sliders 15 by virtue of a cam for the butt 21, which is known and therefore not shown, a forced oscillatory deviation of the slider 15 around the pivot point 20 on the needle bed 40 is carried out and the hook 3 with the elastic buckle 6 of the knitting needle 1 is released by the actuation slider 15 in such a manner as shown in figures 6d and 8d. The knitting needle 1 is hereby ready to be moved into the knitting needle bed 41, whereas the knitted fabric 36 spontaneously moves into the hook 3 of the knitting needle 1, because the presser 39 is situated on the part of the knitting cam system on which this movement is realised, and the elastic buckle 5 of the hook 3 of the knitting needle 1 stays therefore still open. The final position of the needle motion after transfer of the knitting needle 1 is shown in figures 6e and 8e.
The process of forming a purl loop in the knitting needle bed 41 is entirely symmetrical and analogical to the process shown in the series of figures 5a - 5e, and the process of transferring the knitting needle from the knitting needle bed 41 into the knitting needle bed 40 is entirely symmetrical and analogical to the process shown in the series of figures 6a - 6e and therefore will not be described in more detail. For the same reasons a use of the slider in place of the slider 15, or a use of a combination of the two, will not be described.
It is clear from the description of the above embodiments that for transferring the knitting needle 1 between the needle bed 40 and the needle bed 41 (being them either flat needle beds or else circular needle beds of a double-cylinder knitting machine) without forming a new loop, the knitting machine does not require any special mechanism for transmitting the loops, which is the case of using the known double hook knitting needles. The knitting machine is therefore substantially simplified and, in addition, the duration of the production cycle is reduced, as after establishing the purl loop, the subsequent transferring of the knitting needle to a needle bed in which the jersey loops are being established, is made possible by means of a single movement of the carriage of the knitting cam system. It is also clear that there exist no mechanical restrictions as it is the case when knitting needle with actuation pistons are used.
Industrial applicability The knitting motion according to the invention is applicable to all commonly used gauges of the knitting machines and is easily applicable to two-needle bed and four-needle bed flat knitting machines, as well as to double-cylinder small diameter, middle diameter and large diameter knitting machines, whereas by variations of the type of the actuation slider 15 or 23, it is applicable both for more simple knitting machines designed for making only basic reversible structures (wales) and for knitting machines designed for making a knitted fabric with assorted reversible, links-links and cardigan patterns, especially for an automated production of conventional Rnitted underwear.

Claims

1. A needle motion, especially for production of a links-links or a reversible knitted fabric on a knitting machine including at least two needle beds, such as a flat two-bed or four-bed knitting machine or a double-cylinder knitting machine, said needle motion including: a plurality of knitting needles (1), each needle having a stem (2) and two knitting needle heads (3, 4) arranged at opposed ends of said stem; and for each needle, a pair of actuation sliders (15;
23), each slider being provided with a projection (17) for engaging the corresponding needle; characterized in that: each needle head includes a spring hook (3, 4) terminating at a tip (7, 8); the stem of said needles is provided with a pair of curved stem portions (9, 10), each curved portion being arranged in the vicinity of a corresponding one of said tips (7, 8), said curved stem portions having a convexity facing towards the respective tip; each curved stem portion is provided with a first recess (11, 12) for the respective tip (7, 8) and with a second recess (13, 14) for engagement by the projection (17) of the corresponding sliders (15; 23).

2. A needle motion according to claim 1, characterised in that each actuation slider (15; 23) includes at least a bearing surface (16) for the hook (3, 4) of the knitting needle (1), a bevel (18) for causing a spontaneous oscillatory deviation of the actuation slider (15, 23) and pivot point (20) around which said slider oscillates during said spontaneous oscillatory deviation.

3. A needle motion according to claim 2, characterized in that each actuation slider further includes at least one rigid butt (19) for controlling an axial translation.

4. A needle motion according to claim 2 or 3, characterized in that each actuation slider (15) is provided with a further butt (21) for controlling an oscillatory deviation.

5. A needle motion according to one or more of the preceding claims, characterized in that to at least some of said actuation sliders (23) a selector (30) is combined, for selectively activating or de-activating the corresponding actuator slider.

6. A needle motion according to claim 5, characterized in that said selector (30) is swingingly connected to the corresponding actuation slider (23)

7. A needle motion according to claim 6, characterized in that said selector includes a swinging auxiliary actuation slider (30) pivotally connected by means of a joint (29) to its corresponding actuator slider (23), the swinging auxiliary actuation slider (30) being provided with at least one butt (33) designed for application of an axial translation, and a butt (32) for controlling an oscillatory deviation of the actuation slider (23).

8. A needle motion according to one or more of the preceding claims, characterized in that each needle is combined with two actuation sliders (15; 23) of the same type.

9. A needle motion according to one or more of the preceding claims, characterized in that each needle is combined with two actuation sliders (15; 23) of different type.

10. A needle motion according to one or more of the preceding claims, characterized in that a patterning device is combined with at least one actuation slider (15, 23) of said needles (1).

11. A knitting machine including at least two needle beds (40, 41), a plurality of knitting needles (1) and corresponding actuating sliders (15; 23) in each needle bed, for controlling knitting movements and transfer movements of said needles from one needle bed to the other, wherein each needle includes a stem (2) and two knitting needle heads (3, 4) arranged at opposed ends of said stem; characterized in that:
- each needle head includes a spring hook (3, 4) terminating at a tip (7, 8);
- the stem of said needles is provided with a pair of curved stem portions (9, 10), each curved portion being arranged in the vicinity of a corresponding one of said tips (7, 8), said curved stem portions having a convexity facing towards the respective tip;
- each curved stem portion is provided with a first recess (11, 12) for the respective tip (7, 8) and with a second recess (13, 14) for engagement by a projection (17) of said actuating sliders (15, 23).

12. Knitting machine according to claim 11, characterized in that for each needle a pair of actuating sliders is provided, each arranged in one of said needle beds.

13. Knitting machine according to claim 11 or 12, selected from the group including: flat knitting machines with two or four-needle beds, double-cylinder knitting machines.

14. A knitting needle (1) including a stem (2) and two knitting needle heads (3, 4) arranged at opposed ends of said stem; characterized in that:
each needle head includes a spring hook (3, 4) terminating at a tip (7, 8); the stem of said needle is provided with a pair of curved stem portions (9, 10), each curved portion being arranged in the vicinity of a corresponding one of said tips (7, 8), said curved stem portions having a convexity facing towards the respective tip;
and each curved stem portion is provided with a first recess (11, 12) for the respective tip (7, 8) and with a second recess (13, 14) for engagement by an actuation slider.