Patent Description:
In a textile plant, the automatic winding machine includes several winding units that allow the yarn to be unwound from several bobbins or from a reel to wind it into a new reel: during this process, defects are eliminated from the unwound yarn, before rewinding said yarn onto the reel.

It should be noted that the term "yarn" or "monofilament" or "continuous yarn" means a single filament or continuous strand (for example in the case of silk, artificial, or synthetic fibers), while the term "yarn" means the set of fibrils of variable length that are parallelized and joined by twisting. In the following, one or the other term will be used without distinction, it being understood that the applications of this invention are not limited to either type.

On board each winding unit there is a yarn quality control sensor, also called clearer, which verifies the "fitness" of the yarn being unwound; when a defect is detected, the yarn is cut and the winding is immediately interrupted; the cycle then starts with the aim of eliminating the portion of yarn containing the defect from the bobbin and capturing and then bringing the two ends of the yarn (one coming from the reel and the other from the bobbin) inside the joining device by means of two dedicated end gripping nozzles.

For a well-made join of the yarns it is essential that the two yarns are introduced in the right position inside the yarn-joiner device and also with the right tension before starting the joining cycle: in particular, the appearance, the resistance and the repeatability of the joining process are increasingly pressing demands from end customers.

At this point, with the ends inserted, well positioned and tensioned inside the yarn-joiner device, the joining cycle starts, joining the two ends recreating the yarn and one is then ready to start again with the reeling.

The restart after a joining cycle is also a critical step, because the yarn must return to its natural winding path without creating sudden changes in tension or twisting of the yarn which may be seen by the clearer (<NUM>) as defects and generate unjustified cuts, interruptions not due to winding and therefore loss of production.

It is known to use a lever, called the yarn end extension lever, to accompany the yarn end coming from the bobbin in the most suitable position inside the yarn-joiner for the correct realization of the join. Normally such yarn end extension lever takes the motion, through levers and springs, from other mechanisms (bobbin nozzle) and repeats the movement of accompanying and releasing the yarn after joining always in the same way without the possibility of changing the final arrival position and with difficulty to control the return speed.

The types of yarn have changed in recent years and the expectations of end customers on the quality and repeatability of the join have increased: to achieve these improvements it is necessary to take care of every aspect both immediately before joining and immediately after during the re-winding step.

In particular, the known solutions described above are not able to adapt effectively to the different types of yarn, always guaranteeing high standards of repeatability and quality. A solution according to the preamble of claim <NUM> is disclosed by <CIT>.

The need to solve the drawbacks and limitations mentioned with reference to the prior art is therefore felt.

Such a need is met by a winding machine according to claim <NUM> and by a method according to claim <NUM>.

Further features and advantages of this invention will become more apparent from the following detailed description of preferred, non-limiting embodiments thereof, wherein:.

With reference to the above figures, reference numeral <NUM> globally denotes an overall view of a winding machine according to the present invention.

More in detail, the winding machine <NUM> comprises at least one winding unit <NUM>, each having a bobbin <NUM> provided with a yarn <NUM> wound around a tube <NUM>, and a reel <NUM> comprising said yarn <NUM> unwound from said bobbin <NUM> and in turn wound on a relative tube <NUM>.

The winding unit <NUM> also comprises means for unwinding the yarn <NUM> from the bobbin <NUM> and winding the yarn <NUM> onto the reel <NUM> in a known manner.

The winding unit <NUM> comprises a yarn quality control device <NUM>, called clearer, fitted with a quality sensor <NUM> operatively connected to yarn cutting means operable in the event of detection of a defect by said quality sensor <NUM>. The cutting means of the yarn-joiner device <NUM> may be either on the clearer edge or separate.

The winding unit <NUM> also comprises a yarn-joiner device <NUM> configured to join together the yarn ends generated by the cutting of the yarn <NUM> by said cutting means <NUM>, a first end <NUM> being connected to the yarn <NUM> on the bobbin side <NUM> and a second end <NUM> being connected to the yarn <NUM> on the spool side <NUM>.

Advantageously, the winding unit <NUM> comprises a yarn end extension lever <NUM> configured to move from a rest position 28a in which it does not interfere with the winding path of the yarn to a gripping position 28b of the first end <NUM> in which it grips said first end <NUM> and to a release position 28c of the first end <NUM> in which it places the first end <NUM> at the yarn-joiner device <NUM>.

In general, the movement of displacement of the yarn end extension lever <NUM> between the rest 28a, grip 28b and release 28c positions may be a rotary, translational and/or roto-translational movement.

According to a possible and non-limiting embodiment, the yarn end extension lever <NUM> rotates around a preferably vertical rotation axis X-X.

Advantageously, said yarn end extension lever <NUM> is provided with its own independent drive means <NUM> for its positioning between said rest 28a, grip 28b and release 28c positions.

The drive means <NUM> preferably comprise an electric motor. For example, said electric motor is a stepper type electric motor, or a brushless motor, or a DC electric motor or an electric linear motor.

It is also possible to provide, as drive means, pneumatically operated drive means.

Preferably, but not exclusively, the drive means <NUM> are keyed directly onto the yarn end extension lever <NUM>, in direct transmission.

Preferably, the yarn end extension lever <NUM> is provided with a position sensor <NUM> for controlling its angular position.

For example, said position sensor <NUM> is of the inductive or Hall effect type.

Preferably, the yarn end extension lever <NUM> is provided with a control unit <NUM> operatively connected to said drive means <NUM> and to said position sensor <NUM>, so as to control the position of the yarn end extension lever <NUM>.

According to a further possible embodiment, the yarn end extension lever <NUM> and/or the drive means <NUM> are provided with an encoder for controlling the angular position of the lever <NUM> itself.

The drive means <NUM> are operatively connected to a programmable control unit <NUM> so as to vary said rest 28a, and/or grip 28b and/or release 28c positions.

According to a possible embodiment, said control unit <NUM> is programmable to set at least one intermediate working position of the yarn end extension lever <NUM>, between said grip 28b and release 28c positions.

According to a possible embodiment, said control unit <NUM> is programmable to change the speed of rotation of the yarn end extension lever <NUM> to switch between said rest 28a, and/or grip 28b and/or release 28c positions.

It should be noted that the control unit <NUM> which controls the drive means also drives and interfaces with other devices of the winding unit <NUM> or may interface with further control units of the winding unit itself.

The operation of the winding unit according to the invention and therefore the method of controlling the position of the yarn end extension lever into the winding machine will now be described.

In particular, during normal spooling, the yarn <NUM> runs continuously, i.e. it is unwound from the bobbin <NUM> and wound onto the reel <NUM>.

During normal operation, the yarn end extension lever <NUM> is usually in the rest position 28a in which it does not interfere with the sliding of the yarn <NUM>.

In the event of sudden breakage of the yarn <NUM> or detection of defects by the clearer <NUM>, the yarn is cut, the winding is stopped and the two end gripping openings <NUM>, <NUM> intercept the first end <NUM> on the bobbin side and the second end <NUM> on the reel side, respectively.

Therefore, by means of the control unit <NUM>, the rotation of the yarn end extension lever <NUM> is commanded between said rest 28a, grip 28b and release 28c positions of the first end <NUM>.

In detail, the yarn end extension lever <NUM> moves to the gripping position 28b, rotating towards the yarn <NUM> so as to capture the first end <NUM> and bring it, to the release position 28c, at the yarn-joiner device <NUM>.

The yarn end extension lever then returns to the rest position 28a.

According to the present invention, it is possible to provide for the step of modifying said grip 28b and release 28c of the first end <NUM> according to the operating conditions of the winding machine <NUM>, so as to adjust the tension of the yarn <NUM> on the bobbin side <NUM> before the joining cycle by the yarn-joiner device <NUM> and specifically according to the type of yarn used.

For example, it is possible to adjust the yarn tension according to whether it is made up of lycra, cotton, polyesters, wool, mixed elastics, etc..

In fact, depending on the material, the tendency of the yarn to form kinks changes and therefore also the tension to which the yarn must be subjected to avoid the occurrence of such defects.

It is also possible to provide for the step of changing the speed of rotation of the yarn end extension lever <NUM> to switch between said rest 28a, and/or grip 28b and/or release 28c positions.

According to a further possible embodiment, the step is provided of defining/modifying the speed at which the yarn end extension lever <NUM> returns to its rest position 28a after joining has taken place while resuming winding, so as to control the yarn <NUM> on the bobbin side <NUM> and release it, preventing the formation of kinks.

It is also possible to provide for further working positions of the yarn end extension lever <NUM> to be reached while the yarn-joiner device <NUM> makes the join and in a synchronized manner therewith to improve said join both in terms of aesthetics and resistance.

Finally, it is possible to provide for the step of starting to move the yarn end extension lever <NUM> earlier than in conventional solutions and reduce the joining cycle time (position 28b), thus obtaining greater productivity of the single winding unit <NUM> and therefore of the winding machine <NUM>.

As may be appreciated from what is described, the present invention overcomes the drawbacks of the prior art.

Advantageously, the described solution allows the operation of the yarn end extension device to be adapted as desired so as to make it effective and repetitive when the types of yarn used vary.

More in detail, the winding machine according to the invention allows defining and modifying the end-of-stroke of the yarn end extension lever in a dynamic and centralized manner, and therefore "adjusting" the tension of the section of the yarn coming from the spool side immediately before the joining cycle and specifically for each type of yarn (lycra, cotton, polyester, wool, mixed elastic, etc.).

Furthermore, the solution according to the invention makes it possible to define the speed with which the yarn end extension lever returns to its zero position (<NUM>-a) once the joining has taken place while the winding restarts: in fact, it is very important in this transitory step to control the yarn and not release it too quickly, otherwise "kinks" may form which may be seen as defects by the clearer which may cause subsequent stops of the winding since it would interpret these kinks as defects.

In fact, when the clearer sees a false defect (kink), the cycle is repeated and there is a reduction in the overall production of the winding machine.

By virtue of the present invention it is also possible to define further working positions to be reached while the end-joiner device makes the join and in a synchronized manner therewith to improve said join both in terms of aesthetics and resistance.

It is also possible to start to move the yarn end extension lever earlier than in conventional solutions and reduce the joining cycle time (position <NUM>-b), thus obtaining greater productivity of the single unit and therefore of the winding machine.

Different end-joiner devices are available in a winding machine, typically one for each winding unit of the winding machine: the specific end-of-stroke of each end-joiner device (<NUM>-c) may be set either centrally or in a different way for each winding unit, without the need for mechanical adjustments of the yarn end extension lever to adapt it to the device itself.

In addition, it is also possible to obtain a reduction in the maintenance necessary for the change of processing batch.

The implementation of a device according to the present invention facilitates the production steps and reduces the manufacturing times.

Claim 1:
A winding machine (<NUM>) comprising a plurality of winding units (<NUM>):
- a bobbin (<NUM>) having a yarn (<NUM>) wound around a tube (<NUM>),
- a reel (<NUM>) comprising said yarn (<NUM>) unwound from said bobbin (<NUM>),
- means of unwinding the yarn (<NUM>) from the bobbin (<NUM>) and winding it onto the reel (<NUM>),
- a yarn quality control device (<NUM>) fitted with a quality sensor (<NUM>) operatively connected to yarn cutting means (<NUM>) operable in the event of detection of a defect by said quality sensor (<NUM>),
- a yarn-joiner device (<NUM>) configured to join together the yarn (<NUM>) ends generated by the cutting of the yarn (<NUM>) by said cutting means, a first end (<NUM>) being connected to the yarn (<NUM>) on the bobbin side (<NUM>) and a second end (<NUM>) being connected to the yarn (<NUM>) on the spool side (<NUM>),
- a yarn end extension lever (<NUM>) configured to move from a rest position (28a) in which it does not interfere with the winding path of the yarn (<NUM>) to a gripping position (28b) of the first end (<NUM>) in which it grips said first end (<NUM>) and to a release position (28c) of the first end (<NUM>) in which it places the first end (<NUM>) at the yarn-joiner device (<NUM>),
- wherein said yarn end extension lever (<NUM>) is provided with its own independent drive means (<NUM>) for its positioning between said rest (28a), grip (28b) and release (28c) positions,
characterized in that the drive means (<NUM>) are operatively connected to a programmable control unit (<NUM>) so as to vary said rest (28a), and/or grip (28b) and/or release (28c) positions.