EP0078720B1 - Method of knitting stripes or repeating crossbands on a multisystem circular knitting machine, apparatus therefor and products obtained - Google Patents

Abstract

1. A process for the production of stripes or repeating crossbands on a circular knitting machine comprising at least two knitting heads fed with yarns having different appearances, characterized in that, by means of a respective device for selection of the needles associated with each knitting head, each band is started by changing the yarn in use by controlling, on the one hand, the selection device associated with the knitting head whose yarn is already in use in such a way that the needles cease from then on to gather the yarn at this knitting head and by controlling, on the other hand, the selection device associated with the other knitting head whose yarn is not yet in use in such a way that the needles from then on gather the yarn at this knitting head ; the complementary operations being effected at the end of a subsequent band after a whole multiple of revolutions of the cylinders of the machine.

Description

When one wants to obtain transverse stripes on knitted or crocheted articles on circular looms, one generally uses the striping system which exists practically on all circular knitting looms.

With such a system, the change of threads (or colors) takes place at the same fall, by a combined and synchronized maneuver of presentation of the thrower bringing the new thread and withdrawal of the thrower from the old thread.

But there is then necessarily an overlap of the two different threads on a few needles, on which the two threads are knitted simultaneously. In addition, suitable scissors are activated at very precise times, one to drop the end of the new thread which must be knitted, the other to cut and pinch the end of the thread which is withdrawn. The free ends of these two threads are then uncontrolled and are placed in the needles in any positions.

On knitting, the change of threads leads to an excess thickness on some needles, to an irregular mixture of threads of different colors on the few needles on which the overlap takes place and to the existence of loose ends of thread likely to emerge knitting in a very unsightly way.

In addition, this somewhat delicate thrower change operation requires constant control and maintenance of the thread scissors and requires slowing down the knitting speed during the changes.

The invention aims to avoid these various drawbacks. By using a multi-drop circular knitting loom, capable of knitting in jersey or in derivative textures, for example in charged stitches or jacquard, it makes it possible to knit repetitive stripes or transverse bands, of any height which extend over the entire periphery of the article, without cutting the threads at each change. For this, according to the invention, each of the scraps is permanently supplied with a well-defined wire so that at each drop a wire is in work or ready to go into work, while, by means of a selection device needles associated with each fall, each strip is started by changing the thread in work by controlling, on the one hand, the device for selecting the fall whose thread is still in work, so that the needles now stop picking the thread at this drop and, on the other hand, the selection device associated with the other drop whose thread was not in work until then, so that the needles now pick the thread at this drop, the reverse operations being performed at the end of a strip after an integer multiple of turns of the loom cylinders.

This process, which makes it possible to obtain strips having any height in the direction of the mesh columns, has the advantage that there is a continuous mesh of the wires at the transition locations. In addition, the yarn put out of work is not cut and simply extends over the wrong side of the knit to the next area of the knit where it is taken up to work again.

By generalizing the definition of the process, we can say that with a trade comprising a number of falls equal to k.n. the invention makes it possible to knit n strips of different appearance with, for each strip, k scraps working at the same time.

It is also possible to provide for a change of the thread thrower associated with the same drop to increase the capacity of this drop in the use of threads of different appearance.

The invention also extends to multi-fall circular looms suitable for implementing the method. These looms, comprising at least two scraps supplied with different threads and a device for selecting needles which must work at a drop during each revolution of the loom cylinders and those which must on the contrary remain inactive, are characterized in that the means controlling these selection devices are arranged so that the control takes place after an integer multiple of turns of the looms of the loom.

The invention also extends to the knitted articles obtained such as clothing, stockings, socks, etc.

These articles, comprising one or more circular bands of wires of different appearance extending over the entire periphery of the article, are characterized in that the bonding of the wire from one band to the wire different from the adjacent zone of the article is a continuous mesh.

The description which follows with reference to the appended drawing, given by way of nonlimiting example, will make it clear how the invention can be implemented, the particular features which emerge both from the drawing and from the text of course forming part of said invention.

Fig. 1 is a diagram showing a few rows of meshes on a large scale and intended to explain the principle of the invention. Fig. 2 illustrates a variant. Fig. 3 shows the evolution of the yarn (s) of the scraps canceled while knitting takes place on another scribe. Fig. 4 is a schematic view of an embodiment of the control of needle selection cams, adaptable for example to a circular double cylinder loom without a jacquard system. The set of figs. 5a to 5d shows the lining of the needle plates on the lower cylinder of the loom for controlling the selection cams according to the arrangement illustrated in FIG. 4. These figures bear legends which facilitate understanding. Fig. 6 is a schematic perspective view of a circular loom equipped with a thread thrower change device.

• - un fil f1 d'une certaine couleur réalisant la rayure où le bandeau R1 est alimenté à la première chute du métier;
• - un fil f2 d'une autre couleur réalisant la rayure où le bandeau R2 est alimenté à la deuxième chute.

Fig. 1 shows, in jersey context, on the principle plan, a succession of rows of stitches, at the precise place where the thread changes take place:

• - a wire f1 of a certain color making the stripe where the strip R1 is supplied at the first fall of the loom;
• - a f2 wire of another color making the stripe where the strip R2 is supplied at the second fall.

We can, of course, imagine a third wire again, making another stripe and supplied with the third fall, etc.

At the first fall where the knitting of the strip or stripe R1 begins, the needle selection device associated with this first fall initiates the rise of all the needles starting with the needle of the column of stitches M, then brings them in. complete ascent so that all the needles pick thread f1, the picking being followed by normal slaughter. (To fully understand the design, it must be remembered that knitting descends in the loom, as it is made, so that the rows of stitches made first are at the bottom of fig. 1.)

During the entire knitting of stripe R1 (with any number of rows), the other following falls are canceled, so that the needles appear at these falls in the fully slaughtered position, so that they do not pick the threads respective, whose corresponding throwers always remain in the working position.

To stop scratch R1 after a whole number of revolutions of the cylinder, the device for selecting the first fall prevents the ascent, towards the picking position of the thread, of all the needles which follow the last needle to be picked in the column of meshes N. Therefore, the following needles will pass to the first fall in the low position of complete slaughter, without picking the thread f1, whose thrower remains however fixed in position and ready for work.

To continue with the knitting of the stripe R2, the needles, which have all stopped picking at the first fall, are now presented to the device for selecting the second fall, including the cam, which has just been placed in position of work, initiates their ascent, always starting with the needle of the column of meshes M, then the needles are brought in full ascent to pick there the wire f2, picking followed by a normal felling.

During the entire knitting of the strip or stripe R2, all the other falls are canceled, so that all the needles are there in the low position of complete felling, without picking the thread there.

The stripe R2 is stopped on the needle of the column of stitches N, as described above for the stripe R1.

We can chain in the same way with any other wire fed at the third fall if there is one, and so on until the umpteenth fall.

As the threads are not cut when changing from one stripe to another, a float thread ff exists on the reverse side of the knitted fabric, connecting two stripes or bands of the same color in the longitudinal direction.

The last needle having meshed (on the column of stitches N) drives this thread in its displacement on the circumference of the cylinder, without there meeting any obstacle since all the needles knit in jersey and are in low position of felling full.

The wire, thus entrained (f2, fig. 3), therefore sweeps the surface above the lower cylinder (or the free space between upper and lower cylinders, if it is a double cylinder loom) by forming a secant of increasing length from the eyelet of the j2 j2 to the point diametrically opposite to the fall which has just been canceled. For the second half of the cylinder rotation, the secant of the wire decreasing, it is necessary to absorb the excess wire at each revolution of the cylinder by recalling it in the opposite direction through the thrower. For this, an additional fisherman's device P (see fig. 3) can be used, installed at each fall. This device, similar to that which manufacturers build on knitting machines for footwear, for knitting heels and toes in reciprocating motion, or on straight knitters to absorb excess yarn after each end of travel of the carriage, comprises a wire guide P1 mounted on a lever P pivoting about an axis P2 and returned by a spring P3. The lever P pulled by the spring compensates for the slack that occurs in the wire and keeps it taut.

The selection of the needles to knit at one or the other fall is effected by the action of a movable cam disposed at each of the falls and acting on the knitting heels of the plates.

The placing in the operating position and the withdrawal of these cams can be controlled by a set of levers receiving their movements from eccentrics or from cams rotating in synchronism with the movement of the loom, or by an electromagnetic control.

On a circular jacquard knitting loom, the selection of needles to pick the thread at one or the other fall is made from drawing drums and appropriate selectors.

On a double cylinder circular loom without the jacquard system, the needle selection device is composed of two cams, movable in the radial direction and able to approach or move away from the needle cylinder.

One of the cams (which will be called picking lock V1), when it is brought closer to the cylinder, initiates the ascent of the needles to allow picking of the wire; the entry into function of this cam is done on the medium knitting heels Tt.

The other cam (which will be called cancellation lock V2), when it is brought closer to the cylinder, initiates the cancellation of the fall by lowering all the needles to the non-picking position; the entry into function of this cam is on the large transfer heels Tf.

For information and not limitation, fig. 4 schematically shows an embodiment of such a device for controlling the selection of needles, adaptable for example to a double cylinder circular loom, devoid of a jacquard system.

In this figure, Z1 and Z2 respectively represent the lower and upper cylinders of the loom.

The picking bolt V1, when it is advanced towards the needle cylinder, has its inclined ramp facing the path of the knitting heels Tt of the plates 1 which cooperate, as known, with needles 2 of the double hook type.

The function of this cam is to initiate and continue knitting a stripe on the fall of the loom with which it is associated. It is shown in fig. 4 in the radially depressed position, that is to say in the working position where the knitting heels Tt of the plates are forced to climb the ramp inclined relative to the horizontal.

As for the cancellation lock V2, when this is advanced towards the needle cylinder, it has its inclined ramp facing the path of the transfer heels Tf of the plates 1. This ramp, inverted with respect to that of the selection cam V1, aims to cancel the drop considered, always from the same needle, by lowering the needles, at this fall, in the low position of no picking of the wire.

In fig. 4, this cam V2 is shown in its position of maximum radial spacing, so that it has no action.

The control of the cams is programmed by disks 3 driven in rotation in a continuous manner, in synchronism with the rotation of the cylinders Z1 and Z2, and on which are arranged bosses or cams 4 with which the tapping levers 5 cooperate.

When a feeler lever is in a hollow between two bosses, the corresponding selection cam is moved away from the cylinder, therefore out of action.

On the contrary, the passage of a boss under a feeler lever 5 raises this lever which, in turn, actuates the vertical control rod 6.

Via a connecting rod 7, the movement is transmitted to the box 8 located at the end of the radial support rod 9 of the cam V1 or of the cam V2.

A spring 10, placed in the box 8, makes the elastic connection to allow the cam to come into action in two stages. At first, the cam rubs on the smallest heels of the plates, as seen for example in FIG. 5a for the cam V1, and in a second step the cam is in the fully depressed position after the passage of the medium knitting heels (cam V1 in FIG. 5a) or of the large transfer heels (cam V2 in FIG. 5b ).

Springs 11 and 12, acting respectively on the rods 9 and 6, serve to bring all the members back to the starting position as soon as the action of a boss 4 on a feeler lever 5 ceases.

Figs. 5a and 5b allow a better description of the sequence of successive operations for controlling the selection cams, assuming that the loom, comprising two falls each provided with a V1 cam and a V2 cam, is used to knit a sock .

Fig. 5a represents a section of the lower cylinder Z1, at the level of the knitting heels Tt of the plates 1.

In order for the change of the knitted yarn to take place on the rear side of the sock, the selection of needles must be made in the middle of the area of the small knitting heels. The location of needles M and N, which has been discussed in relation to FIG. 1, is shown in FIGS. 5a and 5b. The cylinder rotating counter-clockwise, the needle M and the few needles which follow are provided with plates with medium knitting heel to allow entry into work of the selection cam V1.

To start the stripe R1 at the first fall, the cam V1 is pushed into the working position. After rubbing on a few small knitting heels, it attacks the few medium knitting heels from needle M to start the ascent of the needles which will pick the thread at the first fall. The passage of the few heel means after the needle M allows the cam V1 to enter completely against the cylinder Z1 and, thus, all the needles around the entire periphery of the cylinder will initiate the ascent for the picking of the wire for a whole number cylinder turns.

Of course, all the other falls bringing different wires are canceled, as seen for example for the cam V1 of the second fall.

Fig. 5b shows a section of the lower cylinder Z1, at the level of the transfer heels Tf of the needle plates.

To stop the scratch R1 at the first fall on the needle N after an integer number of revolutions of the cylinders Z1 and Z2, as has been said with reference to FIG. 1, needle M and the few needles which follow are provided with plates with large transfer heels.

During the last knitting round of stripe R1, the cam V2 of the first fall is pushed towards the cylinder (fig. 5b) and it rubs on the transfer heels which cover almost the entire periphery of the cylinder. As soon as the large heels appear from the needle M, they are taken by the cam V2 and are lowered towards the canceling position to prevent the needles from picking up the thread at the thrower. In addition, the passage of the few large heels after the needle M allows said cam V2 of the first fall to come completely against the cylinder and, thus, all the needles are gradually brought into the canceling position. Needle N is therefore the last needle which picked the thread at the first fall.

As soon as the knitting heel of the needle N has reached at least the highest point of the cam V1, and the cam V2 is in the fully pressed position against the cylinder, the cam V1 can be moved away from the first fall for the put out of action.

Immediately after the complete cancellation of the cam V1, the cam V2 can be removed, which completely cancels the first fall.

Of course, during this process, all the other cams V2 on the other falls which bring different wires remain in the position separated from the cylinder.

The invention has various advantages.

In particular, when repetitive transverse stripes are made on a tubular knitted fabric in jersey or fancy stitches derived from jersey, for example charged mesh or jacquard, the invention makes it possible to no longer cut the threads at each change of stripes.

On the other hand, as the change of stripes is done without overlapping of the new thread which starts and the old thread which withdraws, there is no longer any excess thickness of the knitting on some needles, nor irregular and unsightly mixing of these two sons. This results in a very clear and frank delimitation between two successive stripes.

As the respective threads of the different stripes are no longer cut, no free end of thread emerges on the right side of the knit at the location of the changes, hence a marked improvement in the aesthetic appearance of the knit.

In addition, the changes of stripes take place without any slowing down of the speed of the knitting machine.

Since the wire cutter scissors of the scratching devices are no longer used for these repetitive scratch changes, there is less wear and reduction in the frequency of possible incidents with these devices.

As a variant, instead of starting a scratch on the needle of a certain column of meshes M and of stopping this scratch on the needle of the preceding column of meshes N (fig. 1), it is also possible to start and stop on the same needle of the mesh column M ', as shown in FIG. 2.

The structure shown in fig. 1 shows that with each change of stripes, there is no interlining flange, in the places designated by T. Therefore, depending on the quality and fineness of the knitted threads, the interlining tends to spread somewhat at these locations.

The fact of stopping and starting the stripes on the same column of meshes M ′, according to the method shown in FIG. 2, has the effect of tightening the distance between changes in stripes and thus improving the aesthetic appearance of the knitted fabric.

In such an embodiment of the process on a double cylinder loom, the lining of the lower cylinder Z1 at the knitting heels remains unchanged (see fig. 5c).

On the other hand, the few large transfer heels that initiate the cancellation of the fall start from the needle L '(see fig. 5d).

In the embodiments of the method which have just been described, the basic principle consists in making the transverse stripes without overlapping of wires, or unsightly connections, by permanently feeding a well determined wire at each of the different falls. But this has the consequence of theoretically limiting the possible number of different scratches to the number of falls with which the loom is equipped.

However, it is known to provide knitting looms with scratching devices which make it possible to change the thread thrower into work, which makes it possible to increase the possible number of different stripes.

The invention takes advantage of such a device by adapting it suitably, so that it multiplies the number of different stripes or transverse bands which can be carried out at the same fall in the loom, and this while retaining the advantage of n ' have neither overlap nor cut of the threads at the changes of stripes, while ensuring the connection of the threads by a normal mesh.

Fig. 6 shows the principle of operation with change of throwers at one of the falls.

The thrower J 1, bringing the thread f11, is in the working position at this fall and the needles pick this thread under the conditions already described.

Thrower J22, bringing the thread f22 to this same drop, is in the retracted position (out of work), but a vertical guide G prevents the section of thread connecting the last stitch to the thrower J22 from entering the chisel S. The end bottom of this guide has a notch in the direction of travel to prevent the section of wire from escaping from the bottom of the guide.

When it is necessary to change the appearance of the stripe on the fall considered, the permutation of the throwers is carried out while this fall is not working, that is to say while one is knitting a stripe on another fall. The permutation of the throwers can be carried out without slowing down the progress of the loom, because the needles pass without picking at this canceled fall.

When it is necessary to start a new stripe at the fall considered, the thrower with its corresponding thread is already in the working position when the selection cam V1 comes into action to initiate the ascent of the needles.

Note that the guide G is preferably retractable to allow the normal function of the scratching device to be temporarily resumed, for example on knitting machines for footwear for the introduction and removal of the elastic thread at the ribbing, or the reinforcement thread in heels and toes.

On certain types of looms, the retractable guide G can be replaced by a selective command for the operation of the scissors; thus, when a thrower goes out of work, the wire is normally placed in the chisel, but the latter remains open so as not to cut the wire.

It goes without saying that the embodiments described are only examples and that it would be possible to modify them, in particular by substitution of technical equivalents, within the framework defined by the claims.

Claims (14)

1. A process for the production of stripes or repeating crossbands on a circular knitting machine comprising at least two knitting heads fed with yarns having different appearances, characterized in that, by means of a respective device for selection of the needles associated with each knitting head, each band is started by changing the yarn in use by controlling, on the one hand, the selection device associated with the knitting head whose yarn is already in use in such a way that the needles cease from then on to gather the yarn at this knitting head and by controlling, on the other hand, the selection device associated with the other knitting head whose yarn is not yet in use in such a way that the needles from then on gather the yarn at this knitting head; the complementary operations being effected at the end of a subsequent band after a whole multiple of revolutions of the cylinders of the machine.

2. A process according to Claim 1, characterized in that at least one of the knitting heads, fed with a yarn different from that of the other knitting heads, is associated with at least two different yarn feeders, and in that the feeder is changed, without cutting the yarn, during a period when the needles are not gathering the yarn at this knitting head.

3. A process according to Claim 1 or 2, characterized in that the times of selection of the needles are chosen in such a way that the knitting operations of the different yarns at two different knitting heads start in the same column of stitches.

4. A process according to one of Claims 1 to 3, characterized in that the times of selection of the needles are chosen in such a way that the knitting of the different yarns stops in the same column of stitches, which column precedes the column where the knitting started, or is the same.

5. A multisystem circular machine adapted to put into operation the process according to any of Claims 1 to 4 and comprising at least two knitting heads fed with different yarns as well as an assembly of cams for selection of the needles which must be in use at a knitting head during each revolution of the cylinders of the machine and of the needles which must, on the contrary, remain inactive, this assembly being of a controlled variable configuration, characterized in that the means (3,4,5, V1, V2, Fig. 4 and 5) for controlling the change of configuration are set up in such a way that the change is initiated at the end of a whole multiple of revolutions of the cylinders of the machine.

6. A multisystem circular machine according to Claim 5, characterized in that the cams (V1, V2, Fig. 4 and 5) are movable radially so as to be positioned either outside the trajectory of the butts which control the needles (Tt, Tf) or in this trajectory in order to move the butts.

7. A multisystem circular machine also having a double cylinder according to Claim 5 or 6, characterized in that each knitting head is associated with a first movable cam (Vl ) which can act on the knitting butts (Tt) to put the needles into use at this knitting head and with a second movable cam which can act on the change-over butts to put the needles out of use at the knitting head in question, the two cams being controlled at successive intervals determined by the rotation of drums having bosses (3,4) driven in synchronism with the cylinders.

8. A multisystem circular machine according to one of Claims 5 to 7, characterized by the adjunction to the knitting heads of a yarn tensioning device (P1, Fig. 3) which allows the slack of the yarn feeding a knitting head to be taken up when this yarn is not being knitted.

9. A multisystem circular machine according to one of Claims 5 to 8, characterized in that the same knitting head is associated with two or several yarn feeders (J1, J22, Fig. 6) which are interchangeable with one another.

10. A machine according to Claim 9 having a yarn-cutter associated with the interchangeable feeders, characterized in that a fixed or retractable yarn-guide (G, Fig. 6) is provided alongside this cutter (S) to avoid the cutting of the yarn.

11. A machine according to Claim 9 having a yarn-cutter associated with the interchangeable feeders, characterized in that this cutter is fitted with a deactivating device.

12. By way of a new product, an article of knitwear knitted on a circular machine and exhibiting one or several stripes or circular bands in yarns of different appearances, each extending all the way round the article, characterized in that the connection of the yarn of one band to the different yarn of the adjacent zone of the article is one continuous stitching (Fig. 1 and 2).

13. A product according to Claim 12, characterized in that from one band to another, knitted with the same yarn, but separated by a band of different yarn, the first yarn remains continuous from one band to the other by running on the reverse side of the knitting.

14. A product according to Claim 13, characterized in that on the reverse side of the knitting the yarn runs along a line (ff, Fig. 1 and 2) slightly at an angle to the columns of stitches.

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