The present invention relates to open-end spinning or rotor spinning. Open-end spinning machines generally consist of a series of individual spinning units, aligned on the two fronts of the machine, each of which consists of a spinning rotor, which produces twisted thread starting from the singularized fibres of a sliver, and a collection unit which—after controlling the quality of the yarn with the interpositioning of a slubcatcher between the two components—causes the yarn to be wound onto a tube to form a bobbin. This bobbin is thus formed by pulling and winding the yarn onto its surface, as it is pulled in rotation by the underlying roll on which the bobbin in formation is resting. The yarn is spirally wound onto the bobbin in formation as the collection unit is provided with a thread-guide device which distributes the yarn with a backward and forward axial movement onto the outer surface of the bobbin.
The structure of the individual spinning station is illustrated in the scheme of
Proceeding upwards, the single spinning station 1 consists of an actual spinning unit 2 and a collection unit 3, of which the main components which lead to the transformation of the sliver of parallelized fibres to the bobbin of wound yarn are briefly illustrated below.
The feeding tape or sliver S is contained in a cylindrical vase 4 which it is deposited with a double spiral. The sliver S is fed to the unit by a feeding roll 5 passing through the funnel-shaped conveyor 6 and reaches the card 7, a rotating roll equipped with a toothed washer which singularizes the fibres of the sliver S and sends them by suction to the spinning rotor 8, which operates in depression.
The singularized fibres are deposited by a centrifugal effect in the peripheral throat of the spinning rotor 8, which rotates at very high velocities (up to 150,000 revs/minute and over); from here they are collected and removed in the form of the thread F, axially leaving its central opening 9, receiving torsions by the rotation of the rotor itself in the course which runs between its internal throat and said opening 9, thus creating the twisted thread F.
The capturing of the thread is effected with a pair of opposite extraction cylinders 11 and 12 which seize the thread F and driven at a controlled rate according to the arrow a, thus causing the linear production of yarn, generally indicated in m/min. The quality-control sliver 14 of the yarn F can be positioned before the cylinders 11/12.
The thread F thus produced enters the collection unit 3, passes through a thread-presence sensor 15 and encounters a compensator 16 for compensating the variations in length of the run between the spinning unit 2 and the depositing point of the yarn F on the bobbin. The thread-guide device 21 distributes the thread on the bobbin in formation by transversally moving with a backward and forward movement according to the double arrow b, activated by a motor 20 which drives a longitudinal rod 22 in common with the other units of the spinning machine.
The bobbin 25 collects the thread F and is held by the bobbin-holder 26 equipped with two idle and openable counterpoints 27 which become engaged with the base tube 28 of the bobbin. The bobbin in formation 25 rests on its activation roll or collection cylinder 29.
Recently designed automatic open-end spinning machines are equipped with service trolleys which patrol the fronts of the spinning machine and effect the required interventions by stopping in front of the spinning unit which require them.
There are essentially three types of interventions required:
These interventions are generally effected by separating the bobbin 25 from its activation cylinder 29, stopping its movement and allowing the activation of the bobbin 25 or its tube 28 to be effected by an auxiliary activation roll situated on board the service trolley.
In the field of intervention and devices and procedures of automated service trolleys for open-end spinning machines, the applicant is the holder, among other patents, of the following patents IT 1,146,694, EP 340,863, EP 443,220, EP 473,212, IT 1,258,220, IT 1,258,221, IT 1,258,222, EP 1,524,230 A2.
The automation trolley generally consists of a moveable structure along the fronts of the machine, a communication system with the central control unit of the spinning machine and with the spinning units which form the machine, a translation and stopping system of the trolley in front of the units which require the intervention. The moveable structure carries both its control unit and the specific organs or groups of organs for single or multiple operations of the various cycles, which can be required each time and are managed by said control unit.
The present invention can refer to the service trolleys described and claimed by the same applicant in its European patent application EP 1,524,230 A2, to which reference should be made for its structure and essential components.
The present invention relates to a device for controlling the positioning and configuration of the thread-run during cycles operated by the service trolley of an open-end spinning machine.
An objective of the present invention is to provide a thread control and positioning device during intervention cycles of the trolley which allows a greater efficiency of the trolley to be obtained and a greater performance of the spinning machine, in addition to an open-end bobbin of yarn which can be easily used in subsequent utilizations.
In order to better illustrate the problems faced and technical solutions proposed with the present invention, reference is therefore made in the following description to a scheme of a trolley in which the device according to the invention is inserted, at the service of an open-end spinning machine, for illustrative and non-limiting purposes, with the specific indication that it can also be advantageously used in a trolley in which the service groups and organs differ in type and arrangement.
With reference to
FIGS. 4 to 7 show its activation and movement during the depositing phases of the final thread reserve on the completed bobbin.
The device according to the invention is defined, in its essential components, in the first claim whereas its variants and preferred embodiments are specified and defined in the dependent claims.
The trolley organs are managed by the control unit of the trolley itself, which in turn communicates with the central control unit of the spinning machine and with the single spinning stations. The control unit of the trolley coordinates the phases of the intervention cycles, gives activation commands to its organs and receives surveys of the relative sensors and run-ends, controlling the complete or incomplete termination of every phase and taking the necessary measures of the case.
The device 71 is installed,—in the view of
For a preferred embodiment of the intervention cycles, already described in the previous patent EP 1,524,230 A2, a diverting plate 36, having the shape of an asymmetrical and concave hut, is fixed on the internal part of the supporting arm 33. The diverting plate 36 is therefore integral with the worm screw 32 and follows it in its operating and rest positions.
In general, the worm screw 32 has a diameter of 15-30 mm with a smooth-edged thread having a pitch of 4-8 mm. Its activation is in controlled clockwise/anticlockwise rotation with a rate in the order of hundreds of revs/min.
The worm screw 32 has a length which is shorter than the length of the bobbin, as it must carry—rotating in one direction—the thread F from the internal part of the arm 33 to form the initial thread reserve by seizing it between the bottom of the tube 28 and the open counterpoint 27 of the bobbin-holder arm, and on the other hand—rotating in the opposite direction—it must be able to carry the thread F to the opposite free end of the screw 32 and let it fall, in an axial coordinate which is definitely within the range of the thread-guide 21, so that the thread F is hooked thereby to its first useful passage.
The activation motor 35 of the screw 32 can be a brushless motor, or a step-by-step motor, driven—in frequency or by steps—by the control unit of the trolley to obtain angular positions, inversion times and controlled rates in the two rotation directions.
The device 71 for the control and positioning of the thread F so far follows the scheme of the thread positioner of the previous patent application EP 1,524,230 A2.
According to the present invention, in order to allow the depositing of the final thread reserve on the tip of the tube of the completed bobbin, the device 71 for the control and positioning of the thread during the operations of the trolley is equipped with an axial movement organ 72 of the whole device 71 so that the free end of the worm screw 32 can be axially moved to correspond with the winding end of the bobbin, i.e. with the tip of the tube 28. The organ 72 is therefore predisposed for two positions: one drawn back (
As better illustrated in
In the enlarged detail of
The cavity 73 is in cylindrical form and the plug 74 is integrally connected to a sliding piston 75 with a bar 76 which slides guided by a hollow guide 77, on which the contrast spring 78 which tends to push the piston 75 to the left, rests. In order to extend the plug 74, a service fluid is fed under pressure, for example compressed air, with an electrovalve 80 which injects said fluid into the axial cavity 81. When the plug must be withdrawn, the electrovalve 80 is commuted and the fluid is discharged. The thrust of the spring 78 prevails and the plug 74 re-enters the cavity 73.
To illustrate the functioning and characteristics of the device 71 for the control and positioning of the thread during the interventions of the trolley in greater detail, the most important steps are described hereunder, of the operation for depositing the final thread reserve onto the tip of the tube of the completed bobbin before being unloaded, with reference to FIGS. 4 to 7, which show the positions adopted by the trolley organs.
With respect to the re-attachment, removal of the completed bobbin and re-start procedures for the new bobbin reference should be made to their description in EP 1,524,230 A2.
As far as the depositing operation of the final thread reserve onto the tip of the tube is concerned, this operation is effected as follows.
In general, when the length limit envisaged for the bobbin 25 has been reached, the spinning is stopped by providing a signal. Analogously to the re-attachment cycle, the peripheral control unit of the unit lifts the bobbin 25 disengaging it from its cylinder 29, causes the bobbin to brake and requests the intervention of the service trolley. The feeding roll 5 of the sliver S at the spinning unit 2 is also stopped.
When the service trolley C is positioned in front of the spinning unit to be served, the control unit starts the intervention cycle coordinating the operations of the various organs involved. Its lifting group 54 additionally lifts the bobbin 25, leaving it idle; analogously to the re-attachment interventions, the auxiliary activation roll 42 in rotation of the bobbin 25 is brought alongside. The moveable suction mouth 44 for capturing the skein-end of the thread from the side of the bobbin 25, is also brought alongside (
The centralizing device 46 is also activated by lowering it to take the thread F in its gripping fork (
According to a preferred embodiment of the present invention, the length of the thread reserve is easily determined by controlling—on the part of the control unit of the trolley—the number of revs, for which the auxiliary roll 42 is activated in the unwinding of the bobbin 25.
With the coordination of the control unit of the trolley, the device 71 is first brought to a completely extended configuration by activating the axial movement organ 72 so that the free threaded end of its worm screw 32 is axially moved to correspond with the winding end of the bobbin, and also with its cylindrical plug 74 in an extracted position protruding from the threaded part of the worm screw 32, as indicated in
The device 71 is then lifted by rotation of its supporting arm 33 from rest position to the extended position at its maximum height carrying its worm screw 32 adjacent and parallel to the bobbin 25 (
When the centralizing device 46 has completed its lowering and lifting of the device 71 has brought its screw 32 to intercept the immobile thread F, which has been unwound from the bobbin 25 to the extent required by the mouth 44, there is the configuration shown in
In
Starting from the configuration of
According to a preferred embodiment of the present invention, the worm screw 32 is activated at a high velocity so that the rewinding spiral is extremely tilted. With its falling onto the extracted plug 74, the course of the thread F is diverted between the centralizer 46 and the tip of the tube 28, as it is resting on the extracted plug 74. The rotation of the worm screw 32 is stopped, the thread F runs on the smooth surface of the plug 74, with the same axial coordinate: the roll 42 continues to be activated for winding and winds the thread F with clockwise rotation for one or more turns on the tip of the tube to create an identification and attachment point for the skein-end of the bobbin, still recovering the thread from the mouth 44.
According to a preferred embodiment of the present invention, the inversion time of the movement of the worm screw 32 is determined by the control unit of the trolley so as to determine the number of turns of the final reserve thread deposited on the tip of the tube.
After winding the thread F onto the tip of the tube, the winding rotation of the bobbin is continued, whereas the worm screw 32 is restarted, but in an anticlockwise rotation as shown in
The device 71 has therefore terminated the depositing operation of the final thread reserve. It is brought into a withdrawn configuration (
The bobbin is subsequently unloaded, as already described in EP 1,524,230 A2, by opening the counterpoints 27 of the bobbin-holder arm 26 freeing the completed bobbin 25, bringing the arm 43 to its maximum extension to guide the auxiliary activation roll 42 against the finished bobbin 25, to unload it by pushing it towards the middle between the fronts of the spinning machine where a conveyor belt is positioned.
The control and positioning device 71 according to the present invention exerts all the axial positioning functions of the thread within the range of intervention cycles of the service trolley of an open-end spinning machine, including the depositing of a final thread reserve onto the bobbin facilitating its subsequent use.
The device is capable of acting in different ways: it has the possibility of transporting the thread in an axial direction depending on its configurations and positions, with the effective control of its axial coordinate. During intervention cycles, the device 71 preserves the thread from the to-and-fro strokes of the thread-guide and also controls its level. In service cycles there is no concentrated winding of the thread, but the thread is always axially distributed on the generatrix of the bobbin in formation, avoiding accumulations and entanglement.
Number | Date | Country | Kind |
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MI2006A 000008 | Jan 2006 | IT | national |