The invention also concerns a sewing machine, advantageously but not exclusively a multi-needle quilting/ embroidering machine equipped with the device.

The invention also concerns a method to continuously do quilting and embroidery on simple or padded fabrics, wherein it is possible, automatically and independently for every needle, to change the color of the upper sewing thread, or needle thread.

The invention is applied in the textile field and refers to continuous operations, on materials continuously unwinding, of quilting, embroidery etc. , on simple, multi- layer or padded fabrics, with the possibility of making stitches of different colors for all the needles simultaneously, or with different colors for different needles, in an automatic manner and managed by the command computer.

The invention is applied preferentially, but not exclusively, on multi-needle quilting/embroidering machines.

The invention is characterized by the presence of at least: - a transverse bar equipped with ascending-descending movement on which support means are fixed at intervals; an equal number of needle-bearing blocks, of a shape and profile mating with that of the support means, are inserted into said support means on each occasion;

- a fixed transverse bar on which an equal number of actuator assemblies are mounted, at the same intervals, the purpose of which is to change the position of the needle- bearing blocks in the various support means following the ornamental pattern to be made.

BACKGROUND OF THE INVENTION The state of the art includes automatic multi-head embroidering machines suitable to do embroidery with different colors in that they are equipped with heads which have a plurality of needles, normally arranged in a line, where each needle carries a thread of a different color.

Every needle is made to move when the color of the thread which it is carrying is required, while stitching is re- started, at every change of color, by automatically re- positioning the fabric to be embroidered, in order to align the point at which the last needle finished the previous stitching exactly under the needle which has to begin the new stitching with the different color.

The heads of these multi-needle embroidering machines are fixed, and the fabric which has to be embroidered moves on a perpendicular plane below the heads. The fabric is fixed to a frame which is moved in all directions by means of servo motors commanded by the computer following the ornamental pattern to be made.

Document US-A-4,276, 838 describes an embroidering machine with a head equipped with a plurality of needles, associated with relative supports arranged in line and individually driven by a bar with an alternating vertical movement. In order to replace the thread with another of a different color, a lever is activated orthogonal to the vertical movement of the bar, to take a different support in correspondence with the vertically movable bar. The lever moves on a plane substantially parallel to the plane on

which the fabric to be embroidered lies. With this device the sewing can continue with a different color without having to move the fabric from its sewing position.

However, because it performs a lateral displacement of the needles from an inactive position to a working position, this device can only be applied to machines where a single needle at a time, for each sewing head, is involved in the sewing operation. On the contrary, it cannot be applied to multi-needle quilting/embroidering machines, of the type with alternatively movable sewing bars, each of which bearing a plurality of needles, aligned longitudinally, which work simultaneously on a continuously fed fabric. In such machines, in fact, all the needles arranged in line on a bar are fed with a relative sewing thread (needle thread) and simultaneously perform a respective sewing stitch on the fabric moving below them.

In multi-needle quilting machines therefore, the possibility of automatically changing the color of the needle thread has never been taken into consideration, since it has such considerable difficulties.

This limits the possibility of making quilting or stitches with multi-color patterns of varied form and complexity.

The present Applicant has devised and embodied this invention to solve this shortcoming and to obtain further advantages as shown hereafter.

SUMMARY OF THE INVENTION The invention is set forth and characterized in the respective main claims, while the dependent claims describe other characteristics of the invention.

The purpose of the invention is to supply a device, and the relative method, to automatically change the color of the thread of needles on multi-needle quilting/embroidering machines working continuously, that is, on textile materials

unwinding continuously, for example from rolls.

A further purpose is to achieve a sewing machine with the above-mentioned device, suitable to make multi-colored embroideries, also of a complex shape and design, on simple or multi-layer textile materials.

A sewing machine on which the invention is applied comprises at least a first transverse bar equipped with alternate ascending-descending movements, on which support means are longitudinally mounted, advantageously at regular intervals, able to accommodate an equal number of blocks, of a shape and profile mating with that of said support means.

In a preferential embodiment, said support means and said blocks are at least partly arched in shape. In another preferential embodiment, said support means have a conformation at least partly surrounding the relative blocks.

In each of the blocks at least one sewing needle is fixed, which is able to be fed with a relative thread, of a different color or possibly type.

According to the invention, on a second fixed transverse bar, parallel to the movable bar carrying the supports, an equal number of actuator assemblies are mounted, at the same intervals, each of which is suitable to move a plurality of the blocks present on the first bar.

Each of the actuator assemblies is composed of supporting plate means, solid with the fixed transverse bar, to the lower part of which an annular bearing element is fixed with a vertical axis and having a sector missing in the part facing the first vertically movable bar.

In one embodiment of the invention, when there are four colors which can be selected for the needles, the missing sector covers an angle of about 90°.

In cooperation with the annular element, the needle-

bearing blocks not active at that moment are arranged resting with an appropriate protrusion on the upper edge of the annular element.

On the contrary, the corresponding support mounted on the movable bar, containing the block with the needle whose thread is required at that particular point of the ornamental pattern, with every ascending/descending movement of said first bar, passes through the space corresponding to the missing sector of the annular element and to a corresponding hollow of a positioning cylinder.

On the upper part of the supporting plate, fixed on a horizontal support solid with the plate itself, a step-wise motor is mounted, managed by the command computer by means of a drive interface.

By means of a shaft, the motor is suitable to make said positioning cylinder rotate step-wise; the positioning cylinder has on its shell a plurality of equidistant hollows inside each of which a relative needle-bearing block is housed, with adequate play.

In the case where four colors can be selectively selected, the positioning cylinder has four equidistant hollows.

However, it comes within the field of the invention that there are six, eight or more colors which can be selected.

According to the invention, when the motor is made to rotate, for example through angles of 90° or multiples thereof in the case of four colors, the needle-bearing blocks, drawn in rotation in turn due to the contact by the hollows of the positioning cylinder in which they are housed, slide on the inner surface of the annular element on whose upper edge they rest.

From this position the blocks are thrust, in succession, inside the fixed support on the movable bar, wherein they are accommodated perfectly, thanks to the mating form,

advantageously arched, of the two profiles.

According to the invention, the position of the fixed bar is such that when the movable bar reaches the highest point of its alternate ascending/descending movements, the supports fixed thereon are at the same level as the annular elements fixed on the supporting plate of the actuator assemblies mounted on the fixed bar. This allows the needle- bearing blocks to be easily inserted into the support means.

According to the invention, for every change of color the following steps are carried out: - the movable bar, which carries the support means and the needle-bearing blocks, is stopped at the upper dead point where the support means find themselves aligned with the annular elements of the corresponding actuator assemblies, - the step-wise motors are made to rotate, for example through angles of 90° or multiples, in the case of four selectable colors, following the ornamental pattern, - the needle-bearing blocks whose color is required at the moment are thrust into the corresponding support means, expelling at the same time the needle-bearing blocks which were there previously, and which go to rest on the upper edge of the rings, where they stay until the next change of color.

When the thread has been changed, the movable bar is made to move again and the needles start to sew with the new color, following the ornamental pattern until the next change of color.

According to a variant, the rotation of every actuator assembly is coordinated with that of the other assemblies, so as to have all the needles with threads of the same color working simultaneously. According to another variant, every actuator is commanded independently of the others so as to have needles with threads of different colors working

simultaneously.

According to the invention, the rotation of the motors of the actuators does not occur at random, but according to definite rules, to prevent the different colored threads which feed the respective needles and which descend from their respective reels above from crossing each other, thus compromising the regular unwinding thereof.

Moreover, every thread passes through two adjustable thread-braking devices, an upper device and a lower device, which control the tension thereof so as to obtain an ideal stitch.

According to another variant, the upper thread-braking devices are able to be blocked, on command from the computer, for example by pneumatic, electromagnetic systems or otherwise, to prevent the unwinding of the corresponding threads. This serves to prevent the threads of inactive needles from being drawn by the reel which feeds the threads of the needles which are sewing and, continuing to descend, from creating problems of entanglement, or finishing under the needles which are sewing, and are thus sewn onto the material.

Then, the threads of the needles which are sewing slide through the respective thread-braking devices and make the stitches according to the ornamental pattern required, while the threads of the inactive needles are blocked by the upper thread-braking device. Moreover, the threads of the needles which stop sewing must be cut because otherwise they would be drawn by the movement of the textile material to which they are joined.

To this end, in a preferential embodiment of the invention, an equal number of rotary thread-cutting devices are provided for every position of the needles, equipped with two blades; the function of the first blade is to grip

the thread and to draw it for a certain length and the function of the second blade, off-set by an appropriate angle, is to cut it.

The amplitude of the angle between the two blades is such as to ensure that the trailing end of the thread is of adequate length, so that when the needle next starts sewing the thread does not emerge spontaneously from the eye because it is too short. The thread-cutting devices are mounted on the upper part of a fabric-pressing plate, in correspondence with the holes through which the needles pass.

BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the invention will be apparent from the following description, given as a non- restrictive example, of some preferential forms of the invention with reference to the attached drawings wherein: Fig. 1 is a schematic view of an electronically commanded multi-needle quilting/embroidering machine of the type able to comprise a device to automatically change the color of the thread of the needles during continuous quilting/embroidery operations according to the invention; Fig. 2 is a lateral schematic view of a preferential embodiment of the device according to the invention; Fig. 3 is a partial view of the section from A to A of Fig.

2; Fig. 4 is a view from B of Fig. 2; Figs. 5,6 and 7 show respectively in three dimensions the details of the support means, the needle-bearing blocks and the thread-cutting device of the sewing machine according to the invention.

DETAILED DESCRIPTION OF A PREFERENTIAL EMBODIMENT Fig. 1 shows an electronically controlled multi-needle

quilting/embroidering machine 10, of the general type which is substantially known. The quilting machine 10 comprises as its essential parts an inlet assembly 10a, a sewing assembly 10b and an outlet assembly 10c. The inlet assembly 10a is used to feed the textile material 11 which is to be worked.

The sewing assembly 10b comprises upper sewing members 12 and lower sewing members 15 of a conventional type which, cooperating with each other with the respective threads, make stitches on the textile material 11 achieving more or less complex ornamental patterns of quilting or embroidery.

As is well-known, in such multi-needle quilting/ embroidering machines, the upper sewing members are usually needles 12, mounted at pre-set distances on needle-bearing bars 13, provided for this purpose and equipped with suitable alternate ascending/descending movements coordinated with the movements of the lower sewing members 15.

Between the upper sewing members 12 and the lower sewing members 15 there is a fabric-pressing plate 35 able to press the fabric 11 being worked against a striker plane 36.

With reference to Fig. 2, the quilting/embroidering machine 10 is provided with two needle-bearing bars 13, respectively rear 13a and front 13b.

In this case, the rear bar 13a is a needle-bearing bar of the usual type, while the front bar 13b is a special bar and equipped for the automatic change of color of the thread of the needles. However, it comes within the field of the invention that the bar 13a can also be equipped to change the color, or that there may be three or more needle-bearing bars 13.

The front bar 13b is mounted in a more elevated position with respect to the rear bar 13a, and a plurality of supports 14 are fixed on the front part thereof, at regular

intervals.

The supports 14 have an inner surface 14a shaped like a concave circular sector, in this case with an amplitude of about 90° ; they are open on the two sides and on the bottom and comprise a front wall 30, parallel to the inner surface 14a and defining together therewith an open chamber 31 for the positioning and transit of the needle-bearing blocks 25.

Again with reference to Fig. 2, in cooperation with the movable front bar 13b there is a fixed bar 16, solid with the structure of the machine 10; an equal number of actuator assemblies 17 are fixed to the bar 16, at regular intervals corresponding to those of the supports 14 and in correspondence with the supports 14 mounted on the movable bar 13b.

Each of the actuator assemblies 17 consists of a vertical supporting plate 18, solid with the fixed bar 16, on the lower part of which a vertical axis split ring 19 is fixed, whose missing part, which in this case is a sector with an amplitude of about 90° (Fig. 3), faces the corresponding support 14 mounted on the movable bar 13b.

The value of 90° refers to the case shown, with the machine set up for the automatic change of four possible selectable colors. It comes within the field of the invention that there can be 2,6, 8 or more selectable colors, with a correlated modification of the geometric and operational characteristics of the components illustrated hereafter.

With the configuration as described above, with every alternate vertical travel of the movable bar 13b, the support 14 fixed thereto slides between the space of the missing sector of the split ring 19 with very small tolerances.

The position of the fixed bar 16 is such that when the

movable bar 13b is at its upper dead point, the supports 14 mounted thereon are perfectly aligned with the relative split rings 19.

An equal number of orthogonal plates 20 are welded to said vertical supporting plates 18; on each of said plates 20 a step-wise motor 21 is mounted, advantageously associated with an encoder, which, by means of a shaft 22, makes a positioning cylinder 23 rotate. In the case shown of four threads selectively usable, the rotation of the positioning cylinder 23 occurs with angles of 90° or multiples; in the case of a different number of threads, the angle of rotation of the positioning cylinder 23 will on each occasion assume values mating with the number of the threads.

In the shell of the positioning cylinder 23 there are four equidistant hollows 24, of a suitable shape to house, in each hollow 24, with minimum tolerances, a relative needle- bearing block 25, respectively indicated by 25a, 25b, 25c and 25d. The needle-bearing blocks 25 are shaped as a semi- circular section, with an outer diameter mating with the inner diameter of the split ring 19 and with a protrusion 26 facing outwards, in this case dove-tailed, in their upper part.

The protrusion 26 of the blocks 25 not in use (in the case shown 25b, 25c and 25d) is suitable to rest on a mating surface 32 of the upper part of the split rings 19, while the protrusion 26 of the block 25 in use (25a) is suitable to rest on a mating surface 37 of the support 14.

Moreover, the outer diameter of the needle-bearing blocks 25 also mates with the greater diameter of the chamber 31 of the supports 14, while the inner diameter of the needle- bearing blocks 25 mates with the smaller diameter of the chamber 31. Furthermore, in the lower part of the needle- bearing blocks 25 there is a second protrusion 27, opposite

the upper one 26, wherein the hole 33 through which the needle 12 passes and the hole 34 through which the thread passes are made (Fig. 6). The needle 12 is fixed to the relative support 25 by means of conventional attachment means, such as screws or similar, which are not shown here.

The chamber 31 of the supports 14 is such that the needle- bearing blocks 25, when driven by the positioning cylinder 23, can rotate therein freely, rotating inside the chamber 31 with minimum tolerances.

Each actuator assembly 17, as already explained, is able to cooperate, in this case, with four needle-bearing blocks 25, respectively 25a-25b-25c-25d, each of which carries a needle 12 fed with a different colored thread 28.

The device as described heretofore functions as follows.

During the continuous quilting/embroidering of simple or multi-layer textile materials 11, the front bar 13b carrying the supports 14 moves with an alternate ascending/descending movement and the needles 12, fixed to the relative blocks 25 in use at the time cooperate with the lower sewing members 15 to make stitches with the colored threads 28 with which they are fed.

The blocks 25 not in use rest on the split ring 19.

At the moment when, following the ornamental pattern to be made and according to the commands of a computer, it is necessary to change the color of the threads to the needles, the bar 13b carrying the supports 14 is stopped at its upper dead point and the step-wise motors 21 are activated by the computer, by means of drive interfaces, to make rotations of 90° or multiples thereof according to the color of the thread 28, among the four which can be selected, which has to be used.

During these rotations, the positioning cylinder 23 draws the needle-bearing blocks 25 housed in its hollows, making

them slide on the upper edge of the ring 19 and inserting them progressively into the chamber 31 until the dove-tailed protrusion 26 of the block 25 selected is positioned resting on the corresponding surface 37 of the support 14.

The arched form of the inner wall of the support 14 and the outer wall of the blocks 25 encourages the reciprocal sliding in the steps when the blocks 25 are positioned and changed.

In this case, in cooperation with the support 14 there is a retaining device 29 able to hold the selected block 25 in the correct and centered position inside the relative chamber 31. The retaining device 29 comprises, in this case, a spherical clamping element 38 held elastically thrust against the wall of the block 25 by a spring 39. In the wall of the block 25 there is a mating hollow 40 in which the spherical element 38 is positioned in the centered step, when the rotation of the positioning cylinder 23 is interrupted.

In a preferential embodiment of the invention, the motor 21 is suitable to make the positioning cylinder 23 perform a slightly greater rotation than the 90° necessary to achieve the replacement of the block 25, and then return backwards by a corresponding measure. This allows a positioning which permits-the spherical element 38 to be inserted inside the hollow 40, thus encouraging the correct centering of the block 25 with respect to the support 14.

It comes within the field of the invention that the retaining device 29 is of a different type from that shown, for example a pneumatic cylinder, a hydraulic device or otherwise.

The rotation of the positioning cylinder 23, as we have seen, allows to replace a needle-bearing block 25, as desired and automatically, with another needle-bearing block

25 fed by a thread 28 of a different color, or possibly of a different type. The method of change is managed by a computer according to set rules which prevent different threads, fed from respective reels 41, become twisted and entangled with each other.

For example, in the case shown here of four different selectable threads 28, the rotation in one direction of the positioning cylinder 23 does not exceed 270°, at which point, in order to select a new thread 28, the cylinder 23 will rotate backwards to position the selected block 25 in correspondence with the support 14.

In cooperation with the plate 20 there are thread-braking devices, not shown here, which are selectively activated to prevent the unthreading of the threads 28 corresponding to the blocks 25 not in use at that moment, so that the threads, drawn by the action of the reel which feeds the threads which, on the contrary, have to sew, do not create problems of entanglement.

In correspondence with every sewing position of the needles 12, in this case solid with the fabric-pressing plate 35, there are thread-cutting devices 43, associated with respective drive motors 44 able to make them rotate around a substantially vertical axis.

The function of the thread-cutting devices 43 is to cut the thread at that moment of sewing when the change of color is required and the positioning cylinder 23 starts to rotate.

The thread-cutting devices 43 comprise two blades, respectively front 45a and rear 45b, distanced from each other by a certain angle.

The function of the first blade 45a is to grip the thread 28 and draw it for a defined segment, in order to create a trailing end of a certain length; in this way, we prevent

the thread 28, when sewing operations restart, from coming out of the eye of the relative needle 12, obliging the operator to interrupt the functioning of the machine 10 in order to re-thread the needle.

The function of the second blade 45b on the contrary is to cut the thread 28 with respect to the part sewn on the textile material 11, in order to allow the block 25 to be changed.

It is obvious, however, that modifications and additions can be made to the device, method and quilting/embroidering machine as described heretofore, without departing from the field and scope of the present invention.