IT8922411A1 - IMPROVED COMPLEX OF DOUBLE SNAP NEEDLE AND RELATIVE SLIDERS FOR DOUBLE CYLINDER CIRCULAR KNITWEAR MACHINES. - Google Patents

Description

Description of the invention entitled: "IMPROVED COMPLEX OF DOUBLE-NECK NEEDLE AND RELATIVE SLIDERS FOR CIRCULAR DOUBLE CYLINDER KNITWEAR MACHINES"

of SAVIO S.p.A.

Summary

Improved complex of double-beaked needle and sliders for double-cylinder circular knitting machines, in particular for the production of hosiery, in which the jaws placed at both ends of the needle are provided with a blade which is kept in the half-open position by a clip, in the absence of opposing forces, and the tip of the cursor? shaped with a double slope to ensure, during the transfer of the needle from one needle bed to another, the correct position of both the needle and the blade concerned.

Description

The present invention relates to double-cylinder circular knitting machines equipped with double-beaked needles that can work independently in one of the cylinders producing straight stitches and in the other cylinder instead reverse stitches, exchanging said double-beaked needles from one needle bed to the other. 'other.

In such type of machines? therefore a device is provided for transferring said needles from one cylinder to another and? with them it is possible to produce all types of ribbed knits and also all combinations of straight and reverse knits to produce designs, such as for example to produce socks.

How already? mentioned above, these machines are equipped with a particular type of needle, currently called double-beak, schematically shown in figure 1.

For each pair of homologous grooves 1 of the two cylinders 2 of the machine, one upper and the other lower,? placed a needle 3 which is brought alternately to work in the groove of the upper cylinder and in the groove of the lower cylinder. Such a needle 3? substantially symmetrical and d? gifted, at both of its ends? upper and lower, of two equal beaks 4, each formed by a hook 5 and a blade 6, hinged at 7.

Aug 3? moved by a cursor 8 with which it engages alternately with one of the beaks, working to produce knits with the opposite beak. Each needle therefore corresponds to two sliders 8 and 8 ', one placed in the groove of the lower cylinder and the other in the homologous groove of the upper cylinder, which work in turn by hooking themselves to the same double-beaked needle, either on one side or on the other. other.

As shown in Figure 1, the needle 3 engages with its hook 5 of the lower beak in the slider 8, due to the effect of the lower horizontal relief 9 and the upper inclined spur 10, which constrain the needle 3 to slide within the grooves 1 , according to the vertical movements imposed by the cursor 8.

According to the configuration illustrated in Figure 1, the upper lip 4, on the other hand, remains available to work by taking the yarn from the feeders and forming stitches in cooperation with the sinkers 11. The needle-cursor assembly works substantially like a normal circular machine needle, being the cursors equipped with heels for their control by means of cams and counter cams like normal knitting needles. In the configuration shown in Figure 1, the cursor 8? it remains substantially inactive in its groove 1 'waiting for the needle 3 to be delivered to it, exchanging it with the lower slider 8 which then remains inactive in its turn until the needle 3 is delivered to it. works the upper slider 8 '.

The exchange is carried out by approaching each other the two cursors 8 and 8 'at a distance such that their two spurs 10 and 10' are at a distance substantially equal to that between the openings of the two opposite hooks 5 of the needle 3 and moving then to the outside the es-r tremit? of the yielding cursor, which disengages from its beak 4 and can? retract having delivered the needle 3 to the other cursor.

Devices and procedures for carrying out the exchange described above are known from the art and, for example, current user manuals such as the "Technology manual for the knitting industry" by Tremelloni and Ceriani of 1982 or the "Technology manual" can be cited. textile "by Bona, Isnardi and Straneo from 1981.

A device and a method for exchanging the needle 3, according to this known technique,? shown in figure 2. The cursor 8? equipped at the bottom with heels 12 for their control in reciprocating vertical motion, due to the effect of cams and counter-cams not shown in the figure, and with a circular spring 13 which keeps the sliders inside their grooves.

The exchange takes place from the lower cursor 8 to the upper cursor 8 ', which? already? been brought into the lowered receiving position by its overlying control cams. Due to the effect of the underlying cams which operate on one of the heels 12, the cursor 8 is raised to bring the needle 3 into the dotted position to hook its upper hook to the spur 10 '.

In its movement according to the arrow F the cursor 8 pushes the needle 3 with its relief 9 upwards: the upper hook 5 meets the spur 10 'and moves the cursor 8' outwards in order to pass. As soon as the upper hook 5 has passed the spur 10 ', the spring 13 brings the cursor 8' back into position, engaging the upper hook 5 with the spur 10 'and the horizontal relief 9'.

The tip 14 of the 8 and 8 'sliders? shaped, as illustrated in figure 2, receding and flared towards the outside. Said tip 14, when the cursor 8 is raised to deliver the needle 3 to the opposite cursor 8 ', finds on its lifting path a cam 15, currently called eyeglass cam, provided with a hole 16 with outward flaring which intercepts the tip 14 which is rising and moves it towards the outside so that the hook 10 disengages from the beak 4 and does not hold back any more? The needle 3 which is lifted and brought to work on the upper needle bed.

After delivery of the needle 3 to the upper needle bed, the cursor 8 is brought back down and returns inside its groove 1 by effect of the spring 13.

The reverse exchange from the upper to the lower needle bed takes place in the same way by inverting the indices of the illustrated references.

The eyeglass cam also has other holes 16, not shown in the figure, with flaring always outwards but with opposite inclination, to move the sliders placed on the opposite needle bed outwards, when they lower to deliver the needle.

The technical solution illustrated here with reference to Figure 2 has some drawbacks, among which the following are relevant.

The eyeglass cam 15 is very delicate why? it must be thin and hard, and therefore fragile, and? exposed to rapid deterioration and frequent breakage.

The slider 8 must engage the tip of the needle 3 with its flap 6 open correctly, otherwise the flap breaks. According to this technical solution, the correct position of the blade 6? ensured only by the unloading of the stitch formed along the shaft of the needle 3, which does not occur if the feed thread breaks or fails for other reasons. Even in the fortunate case in which the lack of thread did not cause the blades to break during the exchange of the needles, it is then necessary, in order to resume processing, their correct positioning, which must be done manually with a considerable waste of time.

In the pi? recent? A different technical solution has been proposed which allows to overcome the aforementioned drawbacks and which is illustrated with reference to Figure 3.

With respect to the solution just described, the outward displacement of the slider 8, after the needle 3 has been raised to deliver it to the opposite slider, is performed by a radial displacement cam located further away. distant from the tip of the cursor, in place of the eyeglass cam 15, and both the tip of the cursor and the shape of the beak 4 of the needle are modified.

As indicated in the enlarged detail of Figure 3, the jaws of the needles are modified by extending the blade 6 well beyond the hook 5 and the tip 16 of the sliders 8 and 8 'is shaped with an inclination opposite to that of the end. 14 of the previous solution.

These modifications cause the tip 16 of the cursor, as soon as it comes into contact with the beak 4 of the needle 3, opens the blade 6 in the correct position and prevents it from breaking.

According to the sequence of Figure 3 in position A the cursor 8? at its maximum level due to the effect of the lifting cam 17, while the slider 8 'is lowering due to the effect of the lowering cam 18; lowering 8 ', you have its displacement towards the outside why? the spur 10 'is pushed out by the hook 5.

In position B, the cam 18 has brought its slider 8 'to its maximum lowering and the radial cam 19 makes it re-enter the groove, hooking it to the hook 5 of the needle. Needle 3? now in grip with both its 8 and 8 'sliders.

In position C, the radial cam 20 causes the foot of the slider 8 to approach inwards by rotation around a support center C which, on the other hand, causes its tip 16 to move outwards, disengaging the spur 10 from the hook 5. In position D, needle 3? now hooked to the slider 8 'and is carried upwards by the cam 21, while the slider 8 finds the cam 22 which will carry it. then down, now free. This modification makes the needle-cursor complex free from the drawbacks typical of the previous solution, but presents another very worrying one.

In the event that the needle 3 is not correctly sunk into its groove - for example, why? dust or fiber residues or even a piece of thread have entered the groove - when the tip 16 of the cursor 8 moves towards the needle 3, it does not find the blade 6 to open, but finds the hook 5 of the needle and wedges between needle 3 and groove 1, bringing cos? the needle out of the groove. This release of the needles causes the inevitable breakage and the putting out of service of the machine, requiring a very laborious restoration intervention. Such an eventuality is not? unlikely why? the radial size of the needle hook? of 1-2 mm and? therefore a small radial deviation of the needle nose 4 is sufficient, why? the cursor 8 causes this problem when? leads to take the needle.

An attempt is made to remedy this danger by placing a series of sensors in correspondence with the needles to signal any start of radial deviation from the correct position, which must be calibrated over very small distances and which are an inevitable source of alarms and machine stops. , often unnecessary.

The present invention consists of an improved assembly of double-beaked needle and slider which avoids the drawbacks typical of the solutions proposed by the known art and which allows the double-beaked needle to be transferred from one slider to another with absolute safety.

This improvement consists in a modification of both the double-beaked needle and the cursor which are described below with reference to figures 4, 5 and 6 which illustrate a typical embodiment by way of example but not of limitation.

The double-beaked needle is modified, as illustrated in figure 4, by equipping it in both beaks with an elastic device which holds the blade, when? Not ? subject to other forces such as when the beak? without thread, in the open position. That kind of beak? known for a long time in the state of the art, for example for manually operated knitting machines; it ? also described in US patent No. 4827739, which relates to flat knitting machines.

The blade 6 of the spout 4 has a bar clip 23 inserted in the cavity. 24, which extends up beyond the extreme positions that can? assume the pallet 6; said clothespin? supported at its ends and kept in position by a slit inside the cavity? 24 made in the shaft 25 of the needle and which also contains the hinged part of the blade 6.

The end? of the vane 6 adjacent to its pin 7? in contact with the bar spring 23 and? equipped with two flat zones 26 and 27, or at least with less curvature, separated by a terminal zone with greater curvature.

The back of the hinged part of the pallet 6? therefore consisting of a mixed line of which at least one point? constantly in contact with the clip 23.

The two flat areas 26 and 27 allow the blade 6, in its rotation between the extreme positions indicated by the line and point pi? thin, two stable positions 28 and 28 * a stretch pi? heavy from which the blade 6 is moved only at the cost of a greater elastic deformation of the clip 23.

In figure 4 the vane 6? shown with a solid line in one of the two stable positions in which the zone 26 matches the spring 23. In this stable position there is a rather large space 29 between the tip of the blade 6 and the hook 5.

The two extreme positions of the blade 6 completely closed and completely open shown in thin lines and stitches are reached only by loading the spring 23 and occur respectively when the knitting bush is unloaded from the stem of the needle 3 and when the formed knitting bush passes from hook 5 to the needle shaft, as well as? when the slider engages hook 5 with its spur. In the absence of forces which keep the blade 6 in other positions and load the clip 23, the blade 6 assumes the positions 28 or 28 '.

According to the present invention, the tip of the cursor 8 is also modified, which is engaged with the double-beaked needle of figure 4, according to the embodiment illustrated in figure 5.

According to this modification, the slider 8 illustrated in Figure 3 is modified in its tip with an edge conformation 30 with double sloping which performs a double function. In the course of its excursion to take up the double-beaked needle, the cursor 8 first presents its largest part to the hook of the needle. which has an inclination that pushes the needle inwards, in the event that residues of fibers or other material keep it in a position that is not completely sunk into the groove 1, and ensures the correct position of the needle. Its most important part? on the other hand, it has an opposite inclination and the upper edge meets the blade in its upward motion in position 28 causing it to open completely, until it reaches the final coupling position shown in figure 6.

The actuation scheme is substantially that illustrated with reference to Figure 3.

The advantages allowed by the improved needle and cursor assembly according to the present invention are considerable.

In addition to the elimination of the delicate eyeglass cam, the present invention ensures the control of the correct position for both the needle 3 and the vane 6, when the cursor 8 is brought into contact with the double-beaked needle to take it over. from the opposite cursor 8 'and vice versa.

They are also simplified and made more? the control and safety systems of the radial position of the needles are efficient, allowing much more stops and maintenance interventions. limited and only when they are needed.

Claims (4)

Claims 1) Assembly of double-beaked needle and relative sliders, for transferring the needle to work alternately on one or the other needle bed of circular double-cylinder knitting machines, characterized by the fact that the needle beaks are provided of an elastic device which maintains in at least one stable open position 28 the blades 6 of the needles which are not subjected to other forces, and that the tip of the sliders? shaped as a corner with double sloping 30. 2) Assembly of double-beaked needle and relative sliders for double-cylinder circular knitting machines according to claim 1, characterized in that the part of the blade 6 adjacent to its pin 7 has its back constantly in contact with a spring bar 23 and? conformed with two parts 26 and 27 flat, or with less curvature, on the opposite sides of its extremity? with greater curvature. 3) Assembly of double-beaked needle and relative sliders for circular knitting machines with double cylinder according to one or more? of the preceding claims characterized in that the cursor, in its excursion to take delivery of the double-beaked needle from the opposite cursor, first encounters with its double-sloped tip 30 the hook 5 of the needle to be taken over, ensuring its correct position inside the groove of the cylinder and therefore the vane 6 ensuring its complete opening. 4) Assembly of double-beaked needle and relative sliders for circular knitting machines with double cylinder according to one or more? of the preceding claims, characterized by the fact that the radial displacement and approach of the sliders in the transfer of the double-beaked needle from one needle bed to the other of the machine? controlled by cams that intervene on the rod of the slider or on its heels.