DESCRIPTION

[0001] The subject-matter of the present invention is a ring spinning machine of a spinning line, to obtain bobbins of yarn from spools of roving, usually originating from a roving frame.

[0002] As is known, a spinning machine is able to process spools of roving to obtain bobbins of yarn therefrom, after having drafted and twisted the roving.

[0003] For this purpose, the spinning machine consists of a gantry that extends along a longitudinal axis on which are hung the spools of roving, a drafting device placed beneath the gantry consisting of a set of cylinders having longitudinal extension between which the roving passes to be drafted, and a bank carrying the spindles in a row along the longitudinal axis, rotating about their vertical axes, on which the drafted and twisted yarn is wound .

[0004] To increase the productivity of the spinning machine, there are usually two opposite banks, each provided with a row of spindles.

[0005] The spindles are rotated about the vertical axis by a belt driving device, in which the belt is driven by an electric motor and engages spindles of the two banks.

[0006] There exist numerous solutions relating to driving devices for a spinning machine.

[0007] An example is described in the International Applications WO-A1-2009/040734 and WO-A1-2009/040839, in the publication EP-A1-0400260, in the Italian Patent Application No. 10 2018 000 009 103, all in the name of the Applicant. Other solutions are described in the documents US 5,590,514, US 4,944,144, WO-A1-2007/039260 and DE 2125597.

[0008] The current trend in the sector, however, is to provide banks with a very high number of spindles in order to increase the productivity of the spinning line.

[0009] However, the Applicant has found that increasing the number of spindles causes some drawbacks to arise, both in regard to the operation of the spinning machine and in regard to further aspects, such as the execution of maintenance operations.

[0010] For example, it has been found that, when the number of spindles is very high, for example above 1900, it is particularly difficult to maintain optimal synchronization in the RPM of the motors that control the rotation of the spindles, with further technical drawbacks .

[0011] The object of the present invention is to construct a ring spinning machine that satisfies the requirements of the sector and overcomes the drawbacks mentioned above .

[0012] This object is achieved by a spinning machine according to claim 1. The dependent claims define further advantageous embodiments of the invention.

[0013] The features and advantages of the ring spinning machine according to the present invention will be apparent from the description provided below, given by way of non-limiting example, in accordance with the accompanying figures, wherein:

- Figure 1 schematically illustrates a portion of a ring spinning machine according to the present invention;

- Figure 2 depicts a diagram of the spinning machine, according to an embodiment of the present invention.

[0014] With reference to the accompanying figures, a spinning machine of a spinning line for the production of bobbins of yarn from spools of roving S is indicated collectively at 1.

[0015] The spinning machine 1 comprises a gantry 2 extending along a longitudinal axis X, from which the spools of roving S are hung at a predefined height.

[0016] The spinning machine 1 further comprises a drafting device 4 located below the gantry 2.

[0017] The drafting device 4 comprises lower longitudinal cylinders 6, generally three or four in number, motorized, longitudinally continuous or separated in juxtaposed sections, and a plurality of upper rollers 8, typically idle, coupled under pressure with the lower cylinders 6, to be driven by the latter to rotate.

[0018] Each upper roller 8 coupled to the lower cylinder 6 defines a spinning point; for each spinning point, a roving to be drafted passes between the upper roller 8 and the lower cylinder 6 due to the peripheral speed of the lower cylinders, which increases from upstream to downstream.

[0019] Downstream of the drafting device 4, the spinning machine 1 further comprises a bank 10 carrying spindles 12, in a row along the longitudinal axis, rotating about their vertical axes, on which the drafted and twisted yarn is wound.

[0020] The spinning machine 1 further comprises a ring rail

14, with longitudinal extension, provided with alternating vertical motion, carrying rings 16 coaxial to the respective spindles 12, for winding the yarn on the tube .

[0021] Finally, the spinning machine 1 provides for a frame

18, preferably a single one, for supporting the main components, and in particular for supporting the drafting device 4, the bank 10, the ring rail 14.

[0022] Specifically, the spinning machine 1 comprises two opposite banks 10A, 10B, along which are arranged respective spindles 12A, 12B aligned longitudinally, between a head 20 of the spinning machine 1 and a tail 22 of the spinning machine 1.

[0023] On each bank 1 0A, 1 0B , the spindles 12A, 12B are divided into two or more subgroups, in an orderly way from the head 2 0 to the tail 22 . On the first bank 1 0 are thus defined the spindles 12A± _j with i=l...n , where n is the total number of spindles in each subgroup of spindles, and with j=l...k, where k is the total number of subgroups on the first bank 1 0A . In other words, the reference 12An identifies the first spindle of the first subgroup of the first bank; 12A± _j identifies the i-th spindle of the j-th group of the first bank.

[0024] In the same way, the spindles 12 B± _j of the second bank 1 0B are identified.

[0025] The spindles of corresponding subgroups of the first and second bank form a relative group.

[0026] For example, the spindles 12An of the first subgroup of the first bank 1 0A and the spindles 12Bn of the first subgroup of the second bank 1 0B collectively make up the spindles ( 12A, 12B ) i of the first group of the spinning machine 1 . In general, the spindles 12A± _j of the j-th subgroup of the first bank 1 0A and the spindles 12Bi _j of the j-th subgroup of the second bank 1 0B collectively make up the spindles ( 12A, 12B ) _j of the j-th group of the spinning machine 1.

[0027] The spinning machine 1 further comprises a driving device for each group of spindles (12A, 12B) _j , suitable to rotate the spindles of said group of spindles (12A, 12B) _j about their vertical axes.

[0028] Each driving device comprises a belt 30 _j configured to drive the spindles (12A, 12B) _j of the j-th group of the spinning machine 1; said belt 30 _j is arranged along a closed path, tangentially engaging all the spindles of the respective group of spindles (12A, 12B) _j .

[0029] Each driving device further comprises a plurality of electric motors for driving the respective belt. In particular, each belt 30 _j is driven by several electric motors 40 _qj , (with q=l...p, where p is the total number of motors for the j-th group), usually arranged within the closed path defined by the respective belt 30 _j .

[0030] For each group of spindles (12A, 12B) j, said plurality of motors 40 _qj comprises only one master motor with feedback, while the other motors are slaves and operatively connected in parallel to the master motor.

[0031] Each belt 30 _j of one group of spindles (12A, 12B) _j is mechanically independent of the belt 30 _j of another group of spindles (12A, 12B) _j . Moreover, the motors 40 _qj of one group of spindles (12A, 12B) _j are mechanically independent of the motors of another group of spindles (12A, 12B) _j . In other words, for example, there are no mechanical transmission means of the motion between the belt of one group of spindles and the belt of another group of spindles, nor between the motors of one group of spindles and the motors of another group of spindles.

[0032] Moreover, each driving device comprises a drive 50 _j for electrically driving the motors 40 _qj of the respective group of spindles.

[0033] Preferably, the motors 40 _qj of one group of spindles (12A, 12B) _j are electrically independent of the motors 40 _qj of another group of spindles (12A, 12B) _j , being driven by their respective independent drives 50 _j .

[0034] Finally, the spinning machine 1 comprises a control group 60, comprising a control panel usable by an employee to manage the operation of the entire spinning machine 1 and a single logic unit 62, for example a CPU or a PLC, for the control of the spinning machine 1.

[0035] The spinning machine 1 further comprises drafting control means, operatively connected to the drafting devices, for the logic control of the drafting devices.

[0036] Moreover, the spinning machine 1 comprises spindle control means, operatively connected to the drives 50 _j , for the logic control of the motors 40 _qj of each group of spindles (12A, 12B) _j .

[0037] Additionally, the spinning machine 1 comprises rail control means for the logic control of the ring rails 14 of the entire spinning machine 1.

[0038] Said drafting control means, spindle control means and rail control means are operatively linked to the logic unit 62 of the control group 60.

[0039] Innovatively, the spinning machine according to the present invention overcomes the drawbacks mentioned in reference to the prior art.

[0040] In effect, the Applicant has found that it is possible to maintain excellent synchronization between the electric motors, at least in part due to the low wear to which the individual belts are subjected.

[0041] Advantageously, moreover, providing for a plurality of belts, and therefore a plurality of groups of spindles, allows the number of motors engaged with the same belt to be reduced; this allows the power supply of all the motors of the group of spindles, i.e. the master motor and the slave motors in parallel with the master motor, to be maintained substantially at the same voltage.

[0042] At the same time, within the individual group of spindles, the master/slave system allows for the distribution of electrical power between the motors of the group, while the belt ensures the synchronization of the motors . [0043] It is apparent that one skilled in the art, in order to meet contingent needs, may make changes to the spinning machine described above; these changes are also contained within the scope of protection as defined by the following claims.