| JP2003284884 | THREADING DEVICE OF SEWING MACHINE |
| JP2002191884 | SEWING MACHINE |
| JP03143484 | SEWING MACHINE PROVIDED WITH THREADING DEVICE |
| 1. | Device to automatically change the thread in a sewing needle on textile machines, comprising two or more feed reels (14) feeding two or more relative threads (lla, llb) having at least one different characteristic from each other, characterized in that it comprises a threadchange assembly arranged in substantial correspondence with at least a relative needle (12), each threadchange assembly including at least cutting means (19) to cut a thread (lla) fed from a first reel (14), means (22) able to unthread said thread (lla) from the eye of the relative needle (12), means (18,20) able to thread into the eye of the same needle (12) a new thread (llb), fed from a second reel (14), which has to start sewing, and clamping means (21, 29) to clamp the threads which are not in use in order to allow only the thread that has to start sewing to run. |
| 2. | Device as in claim 1, characterized in that said means able to thread the thread (11) into the needle (12) comprise at least a head (18), movable from a first inactive position distant from the needle (12) to a second position close to the needle (12) wherein it positions a hole (32) for the thread to pass through in alignment with the eye of said needle (12), and pneumatic ejection means (20) able to suck in a new thread from a relative reel (14) and send it towards said head (18). |
| 3. | Device as in claims 1 and 2, characterized in that said means able to unthread said thread from the eye of the relative needle (12) comprise a reserve formation assembly (22) able to be selectively activated in order to recover said thread after it has been cut by said cutting means (19) and to return the cut end thereof at least upstream of said head (18). |
| 4. | Device as in any claim hereinbefore, characterized in that said cutting means comprise a cutting blade (19) associated with selectively activable drive means and arranged, at least in use, in a position of proximity with respect to said head (18). |
| 5. | Device as in claim 3, characterized in that in cooperation with each of said reels (14) there is at least a braking assembly (24) for a relative thread (11), and in that said reserve formation means (22) are arranged in an intermediate position between a relative braking device (24) and the threading means (18) and the cutting means (19). |
| 6. | Device as in any claim hereinbefore, characterized in that said means to clamp the threads (11) that are not in use comprise at least a transit pipe (21), at least partly deformable, and a pressure actuator (29) including a rod (26) able to compress a relative pipe (21) in order to clamp therein a relative thread (11). |
| 7. | Device as in any claim hereinbefore, characterized in that said head (18), said cutting blade (19), said pneumatic ejection means (20), said pipes (21) and said pressure actuators (29) are mounted on a plate (15) associated with a cylindrical actuator (16) able to position it between a first inactive position distant from a relative needle and a second operating position near to said relative needle (12). |
| 8. | Device as in claim 2, characterized in that said head (18) includes a vertical groove (31) supporting and adhering to the relative needle (12), said hole (32) through which the thread passes being made on said groove (31). |
| 9. | Device as in any claim hereinbefore, characterized in that said cylindrical actuator (16) is driven in pneumatic, hydraulic, electric or electromechanical manner. |
| 10. | Device to automatically change the thread in a multi needle quilting/embroidery machine comprising at least a bar (13) to support the needles (12), movable with an alternate ascending/descending motion, and at least an assembly to continuously feed a fabric (30) in cooperation with said needles (12), characterized in that it comprises at least a threadchange assembly located in cooperation with at least a needle (12) of said multineedle quilting/embroidery machine and able to automatically replace a first thread (lla) arriving from a relative feed reel (14) with at least a second thread (llb) arriving from another reel (14) and having at least one characteristic different from said first thread (lla). |
| 11. | Method to automatically change the thread in a sewing needle on textile machines, wherein two or more feed reels (14) are used, each able to feed a relative thread (lla, llb, llc) having at least one characteristic different from that of the threads of the other reels (14), and a thread change assembly arranged in substantial correspondence with at least a relative needle (12), characterized in that, in order to replace a first thread (lla) being sewn at that moment by a second thread (llb) having at least one different characteristic, it provides the following steps: the textile machine is stopped with the sewing needle involved in the change in a high position and with respect to a fabric (30) to be sewn; threading means (18,20) and cutting means (19) are brought into a close position near said needle (12); the first thread (lla) is clamped by clamping means (21, 29) located upstream of said cutting means (19) and said cutting means (19) are driven to cut the first thread (lla) between its feed reel (14) and said fabric (30); the clamping means (21,29) are released and the first thread (lla) is recovered in order to return it at least upstream of said threading means (18); pneumatic ejection means (20) are driven in order to insert the second thread (llb) into the eye of the needle (12) making it pass through said threading means (18); the first thread (lla) is clamped by the relative clamping means (21,29) and the textile machine is re started to sew the fabric (30) with said second thread (llb). |
| 12. | Method as in claim 11, characterized in that said step of threading the new thread (llb) into the eye of the needle (12) provides to form a tail of thread beyond said needle (12), sufficient to restart the textile machine immediately with at least 4/5 stitches and to prevent risks that, when sewing is restarted, the needle might be unthreaded. |
| 13. | Method as in claim 11 or 12, characterized in that immediately after the step of recovering the cut thread, the formation of a reserve of thread is provided, taking the clamping means (21,29) into the operating position and picking up a desired quantity of thread from the relative feed reel (14). |
| 14. | Textile machine comprising at least a bar (13) to support the needles (12) and movable with an alternate ascending/descending motion to sew a fabric (30) fed according to the commands of an electronic control unit, characterized in that in a position near said needle bearing bar (13) there is a support element on which at least a device (10) to change the sewing thread in a same needle (12) is mounted, said device (10) comprising two or more feed reels (14) feeding a relative thread (lla, llb, llc), each reel (14) feeding a thread (lla, llb, llc) having at least one characteristic different from the thread present on the other reels (14). |
| 15. | Textile machine as in claim 14, characterized in that said different characteristic is the color. |
| 16. | Textile machine as in claims 14 and 15, characterized in that it is a multineedle quilting/embroidery machine with continuous feed of the fabric (30). |
| 17. | Textile machine as in any claim from 14 to 16 inclusive, characterized in that it comprises a plurality of threadchange devices (10), one for each needle (12) mounted on the needlebearing bar (13), and arranged on a relative support element substantially with the same intervals as the relative needles (12). |
The invention also concerns a method to continuously perform quilting and embroidery on simple or padded fabrics, with which it is possible to change, automatically and independently for each needle, the upper sewing thread, or needle thread; the invention also concerns the textile machine adopting said thread-change device.
The present invention is applied in the textile field and refers to the continuous performance, on textile materials <BR> <BR> continuously unwinding, of quilting, embroidering etc. , on simple, multi-layer or padded fabrics, with the possibility, for example, of making stitches of different colors for all the needles simultaneously, or with different colors for different needles, automatically, managed by a command computer.
In the following description we shall make particular reference to the application of the invention to change the color of the sewing thread, although the device according to the invention can also be used to replace threads with at least one different characteristic.
BACKGROUND OF THE INVENTION Automatic, multi-head embroidering machines are known, suitable to embroider with different colors, and equipped with heads having a plurality of needles, normally arranged in a line, where each needle carries a thread of a
different color.
Each needle is made to move when the color of the thread it carries is required, while with every change of color, stitching is re-started by means of the automatic re- positioning of the fabric to be embroidered, in order to align the point at which the last needle finished the previous stitch exactly under the needle that has to start the new stitch of a different color.
The heads of these multi-needle embroidery machines are fixed and the fabric to be embroidered moves on a perpendicular plane below said 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.
Embroidery machines are also known, for example from US 4.276. 838, which provide a needle store and a movement mechanism to replace the needle working at that moment by another needle carrying a different color in order to change the color, for example, without having to reposition the fabric. This thread-change mechanism is rather complex, bulky, slow and not very reliable, and moreover it cannot be applied in multi-needle machines, for example embroidery or quilting machines, comprising needle supporting bars equipped with alternating ascending/descending movements.
This constitutes a limit to the possibilities of making quilting or stitches with multi-color patterns of various form and complexity.
In conventional quilting/embroidery machines, moreover, in order to change pattern, the fabric has to be repositioned manually every time, and this entails waste of time and effort for the workers.
From the above it can be seen that, in the state of the art, replacing the thread of the needles has always
entailed changing the needle itself, but a device has never been made able to change the thread automatically, for example changing the color, in the same sewing needle.
Applicant has devised and embodied the present invention to overcome this disadvantage and to obtain other advantages as will be shown hereafter.
SUMMARY OF THE INVENTION The present invention is set forth and characterized in the respective main claims, while the dependent claims describe other characteristics of the invention.
Purpose of the invention is to provide a device, and the relative method, to automatically change the thread in a same needle on textile machines, for example, but not only, multi-needle quilting/embroidery machines that work continuously, that is, on textile materials unwinding continuously, for example from rolls.
Another purpose is to achieve a sewing machine, for example a multi-needle quilting/embroidery machine, including the above-mentioned thread-change device, suitable to make multi-colored embroideries, including ones of complex form and design, on simple or multi-layer textile materials.
A sewing machine on which the present invention is advantageously applied comprises at least a bar equipped with alternate ascending/descending movements, on which the sewing needles are mounted, which cooperate in a known manner with lower sewing members, such as shuttles, rotary crochets or oscillating loopers.
According to the invention, in proximity with the needle- bearing bar there is a support element on which at least a relative thread-change assembly is mounted, cooperating with at least two relative feed reels, each one carrying a thread with at least one characteristic, advantageously the
color, different from the thread present on the other reels.
The number of the thread-change assemblies present can be mating with the number of the sewing needles, and they can be mounted on a relative support element aligned and separated with the same pitch as the relative needles.
There are at least two reels with different threads and they may reach a desired maximum number compatible with the bulk, the type of machine on which the device is applied, the type of stitch to be made and the type of textile material treated.
Each of the thread-change assemblies includes means able to automatically perform at least the following operations: - to cut the needle thread, fed from a first reel, which has just finished sewing, - to unthread said thread from the eye of the relative needle, - to thread into the eye of the same needle a new thread, fed from a second reel, which has to start sewing, - to leave a tail of thread long enough so that it does not become unthreaded when the needle starts off again, - to clamp all the threads that are not in use and let run only the thread that has to start sewing.
In a preferential embodiment of the invention, each thread-change assembly has an actuator equipped with a travel converging towards the corresponding needle. When the thread is changed, each actuator makes a support move from an inactive position to a working position. On the support are mounted at least a head to thread the needle, a thread-cutting blade, a pneumatic ejector and suction and clamping pipes for the threads, mating in number with the number of reels.
Moreover, according to the invention, the thread-change
device comprises an assembly to create a reserve, above which are also provided suitable thread-braking devices (one for each thread) through which the sewing threads pass, fed from the relative reels. Each sewing thread passes through the relative thread-braking device which, for example thanks to a pneumatic system, either allows the thread to pass freely, or allows said thread to be subjected to a tension proportional to the load imparted by the spring.
Every change-of-color cycle, commanded by the electronic control unit of the textile machine according to the pattern to be made and the colors selected of the threads to be sewn, occurs with the machine stationary and with the needles positioned in correspondence with the upper dead point, not interfering with the fabric to be sewn, and in a position suitable to cooperate with the head that threads the thread.
BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the invention will become apparent from the description of some preferential forms of embodiment of the invention, given as a non- restrictive example, with reference to the attached drawings wherein: - fig. 1 is a longitudinal section of the thread-change device according to the invention; - fig. 2 is a front view, partly in section, of the thread-change device in fig. 1, - figs. 3a-3q show schematically the thread-change cycle using a thread-change device according to the invention in the case of three different inter-replaceable threads.
DETAILED DESCRIPTION OF A PREFERENTIAL EMBODIMENT OF THE INVENTION Figs. 1 and 2 show a thread-change device 10 according to
the invention, used in a textile machine in order to automatically change, in a same needle 12, the sewing thread 11 for another having at least one different characteristic, advantageously the color.
The textile machine on which the thread-change device 10 is applied can be of any type, although it is preferably used in an electronically controlled, multi-needle quilting/embroidery machine.
Of said machine, of a known type, only a needle-bearing bar 13 is shown in the drawings, with an alternate ascending/descending movement, and a relative needle 12.
All the other components of the machine are here taken as known since they come within the normal knowledge of a person of skill in the art.
A thread-change device 10, as shown in figs. 1 and 2, is advantageously but not necessarily provided for each of the needles 12 carried by a relative bar 13. If the textile machine should have two or more needle-bearing bars 13, all or only some of them can be associated with relative thread-change devices.
The needles 12 act on a fabric 30 which is fed substantially continuously on a supporting plane, and moved in all directions by means of a computerized system.
For each of the needles 12 associated with a thread- change device 10, the sewing threads 11 are fed from relative reels 14. The reels 14 may be of a desired number, compatible with the necessary bulk and with the requirements connected to the sewing process. The number of reels 14 with different threads 11, for example of a different color, which in the embodiments shown as examples here is equal to three, can also be ten or more but in any case it is not limitative in the field of the present invention.
The thread-change device 10 comprises a supporting plate 15 on which are mounted the members provided to perform the thread-change operation, described in detail hereafter. The supporting plate 15 is associated with a cylindrical actuator 16, the function of which is to position the supporting plate 15, and the relative members, from a first, raised inactive position of non-interference to a second, lowered position (shown by thin dashes in fig. 1) cooperating with a relative needle 12 to perform the thread-change cycle.
The cylindrical actuator 16, like the other drive members cited hereafter, is advantageously of the pneumatic type, although it comes within the field of the invention to use hydraulic, electric, electro-mechanical actuators, or any other type suitable for the purpose.
The cylindrical actuator 16 is of the slider type and is equipped with an inclined vertical travel converging towards the corresponding needle 12.
In the following description we shall refer to a change of the color of the sewing thread 11.
When the change-of-color cycle is to be performed, as established by the electronic control unit of the textile machine, each pneumatic actuator 16 makes the relative supporting plate 15 move from the upper inactive position to the lower working position. On the supporting plate 15 are mounted: a head 18 to thread the selected thread 11 into the relative needle 12, a thread-cutting blade 19, a pneumatic ejector 20, and a plurality of suction and clamping pipes 21, one for each thread 11.
The pipes 21 are made of plastic and are associated with an equal number of actuators 29 which, when selectively driven, extend their pressure rod 26 against the relative pipe 21, pressing it against a rear wall 27 and thus
clamping the relative thread 11 inside it. The threads 11 not in use at the moment are therefore clamped in the relative pipes 21, while the working thread 11 can run freely since the corresponding actuator 29 is in an inactive condition with its rod 26 retracted.
Between the supporting plate 15 and the reels 14 there is also a reserve formation assembly 22. In this case, the assembly 22 comprises three transverse round pieces of which one (122) is movable and two (222) are fixed, between which the relative sewing threads 11 pass.
Above the reserve formation assembly 22 there are also respective braking assemblies 24 provided, in this case of the pneumatic type (one for each thread), through which the sewing threads 11 pass, fed from the relative reels 14.
Said braking assemblies 24 consist, in this case, of two disks 124 and 224 made of steel and compressed by elastic means 23, the pressure of which can be regulated, for example, by means of a screw 25, associated with a pressure member 28, advantageously a pneumatic actuator. Each sewing thread 11 passes through the disks 124,224 of a braking assembly 24.
Thanks to the drive of the pneumatic actuator 28, said disks 124,224 can selectively open and let the relative thread 11 pass freely, or can close and subject said thread 11 to a tension proportional to the load imparted by the elastic means 23.
Every change-of-color cycle occurs with the machine stationary and the needles 12 located in correspondence with the upper dead position.
With reference to figs. 3a-3q, where the possible change of three colors is shown, a cycle with the device 10 as described heretofore is performed as follows.
In fig. 3a, the machine is sewing the fabric 30 with the
thread lla of a first color and with the head 18 that threads the needle retracted; the other threads llb and llc are stopped and clamped inside the respective suction pipes 21b, 21c by the respective actuators 29b, 29c, at about 5 centimeters above the head 18. The pipe 21a corresponding to the first thread lla is open, while the pipes 21b, 21c corresponding to the threads llb and llc are closed.
All the braking assemblies 24a, 24b, 24c are closed, and 24a, corresponding to the thread lla being used at the moment determines the sewing tension. The ejector 20 is inactive.
For greater ease of comprehension, in the figures the braking assemblies 24a, 24b and 24c, and the actuators 29a, 29b and 29c are shown in darker when they are closed and lighter when they are open.
In fig. 3b the change-of-color sequence is activated, at the moment when the electronic control unit determines the need to do so according to the design or ornamental pattern to be made. Therefore, the electronic control unit stops the machine and positions the needle 12 involved in the change in a high position. The braking assemblies 24a, 24b, 24c of the three threads lla, llb and llc remain closed.
The actuator 16 moves downwards, bringing the head 18 near to the stationary needle 12. The whole assembly slides on the first thread lla which is held at the upper end by the relative closed braking assembly 24a and at the lower end by the stitch on the fabric 30. Simultaneously, the other two threads llb and llc follow the travel of the actuator 16 recovering the reserve previously prepared in the reserve formation assembly 22.
The head 18 rests on the needle 12 in correspondence with a mating vertical groove 31 and positions a hole 32 for the thread to pass through in alignment with the eye of the
needle 12. The actuator 29a is driven to clamp the thread lla inside the pipe 21a so as to keep it tensed during the cutting.
At this point, the cutting blade 19 is driven to cut the thread lla and, when the cut has been performed, the blade 19 retracts. The three braking assemblies 24a, 24b, 24c remain closed, while the clamping of the first thread lla is released by driving the relative actuator 29a.
Fig. 3c shows the activation of the reserve formation assembly 22 relating to the thread lla in order to recover the first cut thread lla and pull it back to the clamping position at about 5 cm above the head 18.
At the end of this first step, as shown in fig. 3d, the clamping actuator 29a of the first thread lla is driven, and the reserve formation assembly 22 continues its travel, creating a reserve of the first thread lla, taking it from the relative braking assembly 24a, taken to the open position.
The reserve formation assembly 22 remains in its position of maximum travel, while the other two threads llb and llc, which already had their reserve prepared in advance, are not affected.
In fig. 3e it can be seen how the braking assembly 24a of the first thread lla closes, while the clamping system 21b- 29b of the second thread llb to be fed is released.
The ejector 20 is activated with high pressure air in order to thread the second thread llb into the needle 12, thanks to the alignment between the hole 32 of the head 18 with the eye of the needle 12. In this step, beyond the needle 12, a tail of the thread llb is created, taking it from the thread reserve, enough to re-start sewing on the fabric 30 with 4/5 slow-down stitches.
The new thread llb is accompanied by the return movement
of the reserve formation assembly 22 which has been activated with a slow movement in order to prevent the second thread llb from being thrown towards the eye of the needle 12 instead of being accompanied.
The length of the tail of the thread must be long enough to ensure that sewing is restarted correctly, without risk of the needle becoming unthreaded.
When the insertion of the new thread is terminated (fig.
3f), the ejector 20 is de-activated, the actuator 16 retreats sliding on the second thread llb and shortening the tail thereof by about 30mm, but without consequence because the tail length previously created foresaw this.
During the ascent of the actuator 16, the two threads not in use, lla and llc, clamped by the respective clamping systems (actuator 29a-29c and pipe 21a-21c) are loosened so as to create a reserve, but without any consequence because the tension will be automatically restored in the subsequent cycle. The machine can thus be re-started to take up sewing again with the thread llb and the head 18 retracted.
To replace the second thread llb with the third thread llc, the sequence is repeated, starting from fig. 3g.
The electronic control unit stops the machine, according to the pattern that requires the change-of-color, with the needles 12 in the high position.
The three braking assemblies 24a, 24b, 24c remain closed and the actuator 16 returns the head 18 to a position near the stationary needle 12, sliding along the second thread llb held at the upper end by the relative closed braking assembly 24b and at the lower end by the stitch on the fabric 30. Simultaneously, the other threads lla and llc follow the travel of the actuator 16 recovering the threads from the reserve.
The thread clamping system 21b, 29b relating to the second thread llb closes, in order to keep the thread tense during the cutting operation, then the blade 19 is driven to cut the thread and then retreats. The braking assemblies 24a, 24b, 24c remain closed, then the clamping system 21b- 29b of the second thread llb opens.
In fig. 3h, the reserve formation assembly 22 is activated to restore the second cut thread llb to the clamping position at about 5 cm above the head 18.
At the end of this first step (fig. 3i), the clamping system 21b-29b of the second thread llb closes and the reserve formation assembly 22 continues its travel creating a reserve of the second thread llb, taking it from the relative open braking assembly 24b; the reserve formation assembly 22 remains in its position of maximum travel, while the other threads lla and llc already had their reserve and are not affected.
The braking assembly 24b of the second thread llb closes (fig. 31), while the thread clamping system 21c, 29c, relating to the third thread llc to be inserted opens.
As seen in the previous cycle, the ejector 20 is activated with high pressure air and threads the needle with the third thread llc, creating a suitable tail, in the same way as seen above.
Once insertion is complete (fig. 3m), the ejector 20 is de-activated, the actuator 16 retreats, shortening the tail of the third thread llc without consequences, and the other two threads lla and llb, clamped in the relative pipes 21a, 21b, are loosened, creating a reserve, but without any consequence because the tension will be automatically restored in the subsequent cycle. The machine starts sewing again with the third thread llc and with the head 18 retracted.
In the last step to conclude the cycle (fig. 3n), the electronic control unit stops the machine according to the pattern that requires the change-of-color, with the needles 12 in the high position. All three braking assemblies 24a, 24b, 24c remain closed and the actuator 16 returns the head 18 near to the stationary needle 12, sliding on the third thread llc held at the upper end by the relative closed braking assembly 24c and at the lower end by the stitch on the fabric 30. Simultaneously, the other two threads lla and llb follow the travel of the actuator 16, recovering the thread from the previously formed reserve.
The actuator 29c clamps the third thread llc in the relative pipe 21c to keep the thread llc tense during the cutting operation. The cutting blade 19 is driven, which then retreats, while the three braking assemblies 24a, 24b, 24c are closed. Then the clamping system 21c, 29c of the third thread llc opens.
The reserve formation assembly 22 is activated (fig. 3o), restoring the cut third thread llc to the clamping position at 5 cm from the head 18.
At the end of this step (fig. 3p) the clamping system 21c, 29c of the third thread llc also closes, and the reserve formation assembly 22 continues its travel creating a reserve of the third thread llc, taking it from the relative open braking assembly 24c.
The reserve formation assembly 22 remains in its position of maximum travel, while the other two threads lla and llb are not affected.
Finally (fig. 3q), the braking assembly 24c of the third thread llc closes, the clamping system 21a, 29a of the first thread lla to be inserted again opens, and the ejector 20 is activated to perform a new insertion, thus finding itself again in the condition shown in fig. 3a.
It is obvious that the same steps of the cycle are performed when there are four or more threads to replace.
Modifications and variants may be made to the present invention, without departing from the field of protection thereof as defined by the attached claims.