The present invention refers to open end spinning, or rotor spinning. Open-end spinning machines generally consist of a plurality of individual spinning units, aligned on the two sides of the machine, each of which is made up of a spinning rotor, which produces twisted tread from singularised fibres of a rove, and a collection unit that—with the prior quality control of yarn with the interposition of a yarn clearer between the two components—carries the yarn to wind onto a quill to form a cone. This cone is thus formed pulling and winding the yarn on its surface, being pulled into rotation by the roller below on which the cone in formation is rested. The yarn is wound in a spiral on the cone in rotation since the collection unit is equipped with a thread-guiding device that distributes the yarn on the outer surface of the cone with to and fro axial motion.
The structure of the individual spinning station is illustrated in the scheme of
Proceeding from the bottom towards the top, the single spinning station 1 consists of the actual spinning unit 2 and the collection unit 3, the main components of which that lead to the transformation of the rove of fibres made to run parallel in the cone of wound yarn are briefly illustrated hereafter.
The supply band or rove S is contained in a cylindrical vessel 4 where it is deposited in a double spiral. The rove S is supplied to the unit by a supply roller 5 passing through the funnel-shaped conveyor 6 and reaches the card 7, a rotating roller equipped with a toothed trimming that singularises the fibres of the rove S and conveys them by suction to the spinning rotor 8, which works in a vacuum.
In the spinning rotor 8, which rotates at very high speeds (up to 150,000 revs/minute and beyond), the singularised fibres are deposited in its peripheral throat by centrifugal effect; from here they are collected and picked up in the form of thread F, coming out axially from its central opening 9, receiving the twists from the rotation of the rotor itself in the path that runs between its inner throat and such an opening 9, thus generating the twisted thread F.
The pulling back of the thread is carried out with a pair of opposite extraction cylinders 11 and 12 for gripping the thread F and actuated at a controlled speed according to the arrow a, thus determining the linear production of yarn, generally indicated in m/min. The yarn clearer 14 for controlling the quality of the yarn F can be placed before the cylinders 11/12.
The thread F thus produced enters into the collection unit 3, passes by a sensor 15 of the presence of thread and meets a compensator 16 for compensating the variations in length of the path between the spinning unit 2 and the deposit point of the yarn F on the cone. The thread-guiding device 21 distributes the thread on the cone in formation moving transversally with to and fro motion according to the double arrow b, actuated by a motor 20 that commands a longitudinal shaft 22 in common with the other units of the spinning machine.
The cone 25 collects the thread F and is held by the cone-holding arm 26 equipped with two idle tailstocks 27 that can be opened that go into engagement with the basic quill 28 of the cone. For such a purpose the cone-holding arm 26 consists of a pair of prongs 26′ that can be moved apart in the axial direction to separate the two tailstocks 27 and insert the new quill 28, or else discharge the finished cone 25.
The cone in formation 25 is rested upon its actuation roller or collection cylinder 29.
Recently conceived automatic open-end spinning machines are equipped with service trolleys that patrol the sides of the spinning machine and carry out the required interventions stopping in front of the spinning unit that requires it.
The required interventions are essentially of three types:
Generally, such interventions are carried out by separating the cone 25 from its actuation cylinder 29, stopping its motion and actuating the cone 25 or its quill 28 by an auxiliary actuation roller arranged on-board the service trolley.
In the field of devices and procedures for the intervention of service trolleys on automated open end spinning machines the applicant is the owner, amongst others, of 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.
In general, the automation trolley consists of a structure mobile along the sides of the machine, a communication system with the central control unit of the spinning machine and with the spinning unit that make up the machine, a translation and stopping system of the trolley in front of the units that require intervention. The mobile structure carries on-board both its control unit and the members or groups of members dedicated to the single or multiple operations of the various cycles, which can at various times be required and which can be managed by said control unit. The present invention is relative to a device for the insertion of the new quill between the two tailstocks of the cone-holding arm and for the initial winding of a length of thread at the base of the quill itself to constitute the initial reserve of a very compact cord of thread in the starting and lifting cycles carried out by the service trolley of the open-end spinning machine.
The purpose of the present invention is that of making a device for engaging the quill between the tailstocks that gives an effective deposit and firm attachment of the initial reserve of thread on the empty quill, before restarting the normal winding for the production of the new cone on the replaced quill.
Indeed, it should be taken into account that in the transitory steps, like in that of the start of winding on the new quill, there are significant differences in speed between the members involved, from which derive different tensions. For example, the speed of removal from the actual spinning unit 2 carried out by the cylinders 11, 12 quickly reaches the operating speed, whereas the collection unit has a slower acceleration ramp. Added to this there is also the pulsation caused by the thread-guide that, with its forward and backward motion, periodically lengthens and shortens the path of the thread increasing and decreasing both its collection speed and its tension.
Such a reserve has different functions during the course of the subsequent treatments of the yarn. Amongst these a rather important one is that of allowing the prior connection of the end of a cone, or rather of the coils of the reserve, with the start of the next cone, unwinding them during their use to produce fabric on a frame or on circular knitting machines.
The tension with which the initial thread is wound on the new quill to form the reserve on one of its ends is important. Such a tension gives the spirals of thread a cohesion and a compactness of the cord that makes it more difficult for it to slacken and unwind spontaneously.
For this purpose the reserve is deposited with a small traversing movement so that the coils are not parallel but slightly crossed and overlapping. However, there remains the problem deriving from the fact that the deposit of the reserve must take place with the thread already in formation that is sucked up by a mouth and eliminated: it must be cut and winding must begin instantly without the thread slackening.
An insufficient, or even just variable, tension generally produces an unstable reserve cord, which tends to slacken and drop coils or portions of thread from the cones during transportation or their arrangement in crates or chests. These slack threads of cones or of packages in general cause knots or become entangled in the parts with which they come into contact, making both transportation and automatic distribution of the cones, and the unwinding and use of the deteriorated, or even missing, reserve of thread very difficult.
According to patent EP 340.863, to the same applicant, the tautening of the thread is carried out by gripping it on the distributor pad of the reserve, operating with the new quill already placed in rotation at the operating speed resting it on its actuation cylinder 29. This way of proceeding to the depositing of the reserve and to the closing of the cone-holding arm already at full speed involves risks of uncontrolled sideways movements of the quill in this transitory step, especially if one is operating with frusto-conical quills.
The present invention refers to a device for firmly attaching the quill and for depositing the reserve of initial thread on the quill operating at a partial speed and with greater control of the quill and of the thread, which overcomes the drawbacks of devices available in the state of the art and allows a compact reserve of thread to be deposited on the quill with greater constancy and reliability.
To better highlight the problems tackled and the technical solutions proposed with the present invention we thus refer, in the following description, to a scheme of a trolley in which the device according to the invention is inserted, for servicing an open-end spinning machine, as a non-limiting example, with the explicit warning that it can advantageously also be used in a trolley in which the groups and the service members are different in type and arrangement.
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.
As well as these groups, for the lifting and starting operations the following are foreseen:
On the cone-holding arm 26 of the open-end spinning station, one of the two prongs 26′, and in particular the one at the side of the base of the quill 28 on which the reserve must be deposited, the device 31 for firmly attaching the quill and for depositing the reserve of initial thread on the quill according to the present invention is arranged, which is described in greater detail in the following
The members of the trolley are managed by the trolley's own control unit, which in turn communicates with the central control unit of the spinning machine and with the individual spinning stations. The trolley control unit coordinates the steps of the intervention cycles, imparts the actuation commands to its members and receives the detection thereof from the relative sensors and end stop, checking the positive outcome or not of each step taking the measures to suit the case.
To illustrate the operation and the characteristics of the device 31 for firmly attaching the quill and for depositing the reserve of initial thread on the quill the lifting cycle is described in its significant steps with reference to
In general, once the limit length foreseen for the cone 25 has been reached the spinning is stopping giving off a signal. As for the reattachment cycle, the peripheral control unit of the unit takes care of lifting the cone 25 disengaging it from its cylinder 29, braking the cone itself and requesting the intervention of the service trolley. When the service trolley C had arrived in position in front of the spinning unit to be serviced, its raising group 54 further lifts the cone 25, leaving it idle; the arm 43 is then rotated up to its maximum extension to take the auxiliary actuation roller 42 against the finished cone 25, to discharge it with a push towards the middle between the fronts of the spinning machines where a conveyor belt device, already known in the prior art, periodically evacuates the finished cones that have been pushed into the middle between the two sides of the machine. For the sake of simplicity of drawing, such parts are not shown in
As already stated, the raising group 54 also 20′ operates the opening and closing of the tailstocks 31 of the arm 26 for the discharge of the finished cone and the insertion of a new quill 28. The quill-holding group 64 and its gripping and presentation member 65 of the new quill that will have to constitute the support on which the new cone 25 shall form is also brought closer.
The introducing group 52 withdraws to take and grip the auxiliary thread A between its members and advances into the position shown in
As shown in
The newly produced thread is sucked with the mouth of the member 60 and is introduced into the thread sensor 15. With such suction the portion of auxiliary thread used for reattachment is sucked up and eliminated. The gripping member 60 is advanced further towards the spinning unit inserting—in cooperation with the device 41—the new thread between the base of the quill 28 and its tailstock 31 that is still open.
The engagement step of the newly produced thread with the new quill 28 is described with reference to
As shown in
The base of the toothed tailstock 31 consists of a disc 32 and a slightly conical neck 33, coaxial with the disc 32, and with a diameter such as to receive and hold in position the inside of the quill 28. The peripheral crown of the disc 32 constitutes the seat for the quill between the two tailstocks.
On the flat outer face of the neck 33—and preferably on its periphery—a skew pyramidal toothing is made formed from teeth 34, having a face 35 inclined with respect to the face of the neck itself and the opposite face 36 substantially perpendicular to it. On the outside of the teeth 34 a chamfer 38 for receiving and centering the quill is made.
As shown in
The skew pyramidal toothing is applied with a number of teeth 34 preferably between 8 and 20. The inclination of the inclined wall 35 of the teeth 34 is from 20° to 50° with respect to the plane from which they project.
The toothed tailstock 31 for the cone-holding arm performs the double task of tautening the thread during the formation of the reserve and of eliminating the risks deriving from sideways movements of the quill on the set 65. Indeed, the device allows the closing of the tailstocks and the starting of rotation of the quill to be carried out simultaneously.
The procedure is carried out as follows.
At the start, the thread F continues to be produced and to flow in the mouth of the device 60, the cone-holding arm 26 is completely open, the new quill 28 is immobile, presented between the open tailstocks and lifted by the cylinder 29. The mouth 60 moves to place the thread F between the base of the quill 28 and the toothed tailstock 31, continuing to suck it. The device 62 engages the thread F in the configuration of
From such a configuration, in quick succession the quill 28 is placed in rotation with the roller 42, the cone-holding arm 26 is closed, the thread F is cut by the scissors 68 of the mouth 60 and the oscillating pad 62′ is actuated, which carries out the traversing to form the reserve of thread.
In this step the thread F is firstly trapped between two opposite teeth, for example D1 and D2, and is then gripped between tailstock 31 and quill 28, then pulled into rotation by the teeth of the tailstock 31. Their shape, as shown in
The skew toothing with the teeth 34, in the brief time period of the closing step in which the quill that is already rotating presses the thread against the seat 32 of the tailstock that is still stationary, ensures that the thread F, which is the first to come into contact with the edge of the rotating quill, in any case remains held in diametric position by the steep wall 36 of the teeth 34 that are still stationary, until the closing of the cone-holding arm 26 and of the tailstock pulled into rotation by the quill.
For this purpose it should be noted that the outer edge 38 of the chamfered teeth allows the thread F not to be gripped but only trapped—i.e. held in diametric position—until the base of the quill 28, in the closing of the arm 26, rests upon its seat 32.
The toothed tailstock device 31 carries out the certain pulling into rotation of the thread without the possibility of losing it, as, however, can occur with a conventional tailstock, without toothing.
For considerations of geometry and tolerances, the thread may not be gripped simultaneously in the two opposite points at the inner circumference of the base of the quill and outer circumference of the seat of the tailstock: the rotation of the quill 28 tends to carry the portion of thread outside of the grip of the stationary tailstock before it closes tight, thus not allowing it to be gripped.
Having carried out the connection of the reserve of thread to the end of the new quill 28 and having re-established the normal path of the thread from rotor 8 to cone 25, the normal winding of the new thread F, which is freed, restarts. The quill 28 of the new cone in formation is lowered on its cylinder 29, whereas the thread is hooked by the thread guide 21 at the first useful passage. The trolley has completed its task, can withdraw its members to rest and be directed towards other units of the spinning machine.
The toothed tailstock device 31 according to the invention is able to carry out the tautening and control of the thread during the formation of the reserve, keeping the quill in correct position during such an operation. The device allows—within an automatic service trolley for open-end spinning machines—the closing of the tailstocks and the starting in rotation of the quills to be carried out simultaneously. The toothed tailstock device has substantial progressions with respect to devices of the prior art. The possibility of carrying out the operation of starting winding and of depositing the reserve of thread at a partial and controlled speed is very important.
The reserve of thread is deposited with greater reliability and constancy of quality as regards its compactness and hold on the quill.
Number | Date | Country | Kind |
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MI2003A 002006 | Oct 2003 | IT | national |