CS231367B1 - A method of providing a reliable operation of the knitting machine and a tensile force monitor of the tensile force in the thread to perform this method - Google Patents

Abstract

The subject of the invention is a method of ensuring reliable and efficient operation of a knitting stand by eliminating failures in the yarn supply system using a yarn supply loop with a length sensed by the action of a pressurized gaseous medium. The essence of the invention is the independence of the reaction to the tripping force, which causes the shortening of the yarn supply loop in the event of a failure in the supply system, on the magnitude of the speed and changes in the yarn speed and has a constant value that can be centrally and remotely adjusted. The device consists of a chamber equipped with a flange for supplying a low-pressure gaseous medium, a position sensor for the guiding element, at least one chamber for capturing impurities, a means for slowing down the movement of the guiding element in the chamber when shortening the length of the supply loop behind the guiding element and an element for hanging the catch on the guiding element by the yarn by means of a pressurized gaseous medium.

Description

A method for ensuring reliable operation of a knitting machine and a tensile force detector in the yarn for carrying out this method

It is an object of the present invention to provide a reliable and efficient operation of the knitting machine by eliminating disturbances in the yarn feed system using a sensed length stock loop under the action of a pressurized gaseous medium. The essence of the invention is the independence of the response to the cut-off force, which causes a shortening of the yarn supply loop in the feed system failure to the magnitude of the speed and changes in the yarn speed and has a constant value centrally remotely adjustable. The apparatus consists of a chamber provided with a flange for the supply of low-pressure gaseous medium, a sensor for positioning the guide, at least one dirt collecting chamber, means for slowing the movement of the guide in the chamber while shortening the length of the supply loop behind the guide. The element is threaded by means of a pressurized gaseous medium.

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BACKGROUND OF THE INVENTION The present invention relates to a method of providing reliable and efficient operation of a knitting machine, in particular a volumetric knitting machine, by eliminating disturbances that occur during the knitting process in the yarn feed system from bobbins to knitting needles. media. The subject of the invention is also a corresponding device, which is a reservoir tensile force monitor in the thread.

In the technological knitting process, the yarns are unwound from the bobbins and supplied to the knitting needles by the feed system.

Due to the varying quality of the winding, the threads often unwind, causing the threads to break in the feed system, the defects in the knitted fabric and the throughput of the knitting machine. The failures described are due to many other causes, such as backed-up spools by poor overhang from unwinding spool to back-up spool, slipping off the last layers of spool from spool and blocking tufts in the guide eye, passing knots through the brake,

Currently, the knitting machines are equipped with so-called nile watches of various designs, which can be divided into two groups. * They are thread free end guards and impact guards. The thread end detectors stop the knitting machine if the thread integrity in the feed system is broken. Impact detectors are intended to prevent yarn breakages in the feed system by dampening the yarn tensile force tip when it is blocked, sending a signal to stop the knitting

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- 2 • three threads and loosens a certain thread length that wears out the machine run-out · however, the corrosive impact detectors in the thread meet only partially and imperfectly ·

The most widespread type of yarn impact detector used is based on a spring-loaded lever ending with a forked guiding element in which the yarn moves. · When the set directive force is exceeded, the lever flips, the built-in contact commands the machine · Before starting the machine again, it is necessary to manually set the guard and re-hang the thread into the guide element. by positioning the watchdog, directing the yarn from the guide element and a considerable proportion of the inertia forces resulting from the moment of inertia of the lever or other inertia weights. Another drawback in the operation of this watchdog is the fact that the shutdown occurs on a relatively small path, while at the same time a steep increase in directive force. When setting the directive force of smaller values, the knitting apparatus is switched off and stopped due to shocks of short duration, which leads to unnecessary downtime of the knitting machine and necessitates repeated manual handling. On the other hand, when adjusting the higher values of the direct force, the tensile force shocks multiplied by the wraps on the guide eyes of the feeding system of such a size that they penetrate the feeder cause breakage only in the knitting needles, causing defects in the knitted fabric. In addition to the conventional thread impact detectors just described, systems are known to eliminate the need to thread the thread after the detector has been fitted. which necessarily leads to yarn breakages, especially in the case of the use of textile materials · low flexibility · hence this type of guard is used only to a minor extent ·

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In sheet metal knitting machines, in which the cc carriage moves reciprocally, ac releases the workpiece at the dead center of the eye movement. Even when moving from the edge of the knitted fabric to its dead center, the conductor further draws the yarn from the pattern, so that at the beginning of the knitting of the next row the yarn in the undesired hole is released. This loose yarn is to be leveled so that the first needles forming the next row receive the yarn in an appropriately tight state and that the first stitches are not thinner than the other stitches of the row. In the reversible knitting process on a small diameter circular knitting machine, a similar ** yarn loosening occurs, with the * difference * that the conductor rotates there and moves the needle cylinder. Due to the dough side effects and the inertia of the tensioning devices, the knitting speed must be maintained in certain knives.

In order to overcome these drawbacks, the yarn tensioning device on the knitting machines of FIG. No. 137,923, which is arranged * between the master and the conductors *. It is formed by a hollow body which is connected to a vacuum source. The hollow body is movably mounted with a piston which, on a worn away from the nose vacuum source, has a yarn eyelet for which the hollow body is open to the even * end Supporting and guiding surfaces · The yarn is like this on the way between the pattern and the wires * tensioned by the soil * of the vacuum and the piston, while the vacuum can be adjusted. In this solution, the influence of inertia forces is not eliminated, which leads to an increase in the yarn tension and shocks *. The force exerted on the piston by the action of the vacuum is unchanged in any position.

It is an object of the present invention to overcome the described disadvantages of the existing method of securing the integrity of the processed yarns and to provide a machine functionally superior which makes it possible to improve the quality of the knitted fabrics and improve the time utilization of the knitting machine.

The essence of the proposed method of absorbing tensile force impacts in the thread is the realization that high values of tensile force exceed! often the strength of threads, finds origin in short-term * sudden *

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- 4 • lowering the axial velocity of the unrolled yarns to which the inertia masses of the guards respond according to the second motion lawn. force, ie · the force transmitted by the yarn to the shock monitor and causing its operation is equalized by the rs, consisting of the direct and inertia components · The latter is proportional to the deceleration of the yarn, the inertia, or the moment of inertia of the moving parts · Shocks and is in part comps with absolute thread extension ·> the rsakes is usually the usual component · produced by spring, magnetic field or gravity ·

The method of absorbing shocks of the tensile force according to the invention is characterized in that the inertial component of the tripping force is eliminated to a maximum extent. The directive component is constant while forming a yarn stock loop whose length is sensed and ensures correct stopping after stopping · Due to its elasticity, the stock loop also assists in absorbing any residual inertial forces. · The magnitude of the shut-off force of the watcher · the thread impact is independent and changes in the yarn unwinding speed only due to the directive component

The device for ensuring the reliable operation of the knitting machine consists of a chamber provided with an inlet and an outlet for the thread with a supply of pressure medium. A guide element is provided in the chamber, which is equipped with a thread catch. The chamber is provided with a flange for supplying a low pressure gaseous medium, providing a guide position sensor, at least one dirt trapping chamber, a means for slowing the movement of the guide element within the chamber while shortening the length of the feed loop with mammalian thread . The means for slowing the movement of the guide element is a one-way valve. The Xlsmont thread-fixing hook is attached to the rear of the chamber, the flange of which forms the bearing surface for the unidirectional vontile.

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- 5 The guiding element position sensor consists of at least two electrical contacts which are pneumatically operated depending on the position of the diaphragm. · One of the electrical contacts is formed by a metallic coating on the inside of the diaphragm and the other contact forms a flat connection.

The device for carrying out the method described in the form of a yarn tensile force monitor is shown schematically on the attached yarn. The yarn tensile force monitor consists of a plenum chamber 1 provided with an inlet and outlet opening for the yarn N, flanges 2 for supplying pressure medium. The guide element 8 is provided with a catch 8 for thread tension N. The pressure chamber 1 further comprises a sensor 2 of the guide element 8, which is formed by a diaphragm 11 and a pair of electrical contacts 12. In the technologically advantageous embodiment, the chamber 1 is of rectangular cross-section, which at the same time ensures correct axial orientation of the guide element 8, which is also of rectangular cross-section and flush with the opening in the chamber 1. It is made of a low density material, e.g. Alloy wood or fiberglass shell · The guide element moving slidingly in the chamber 1 is equipped with a stainless steel wire catch 8, coated in the hook area with, for example, enamel or corundum coating to ensure good sliding properties and low abrasion · Chamber 2 P ^ro the dirt trap is located in the rear part of the chamber 1 in the space below the catch hook 8 and is provided with a lid 9, preferably suitably perforated, for sucking up the dirt released mainly by the abrasion of the thread on the hook as a one-way valve having a low flow resistance of the gaseous medium when the guide member 8 moves from its working position when the supply loop is shortened and a large flow resistance when the guide member 8 moves in the opposite direction. made as a guide Ovation collector seeded

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6 at the rear of the chamber 1, its flange 10 forming a bearing surface for the foil of the unidirectional valve, i.e. means 6. In a preferred embodiment, the signaling indicator is realized by a light-emitting diode 18 switched by contact of the sensor 2

The advantage of the inventive yarn tensile force detector according to the invention is, above all, reliable damping of the tensile force in the yarn, which results in the removal of yarn breakages, an increase in the quality of the knitted fabrics and savings in the base textile material. As a result of the dropping of the threading operations in the feed eyelet, the labor and labor of the knitting machine operator is reduced and the prerequisites for widening the knitter's working area are created. The device according to the invention is particularly suitable for mounting on separate creeling circular knitting machines. Eliminating tensile force impacts in the thread also reduces the demands on the quality of feeders and thus their cost. The cut-off force of this shock absorber is determined by the pressure of the gaseous medium and can be easily adjusted centrally and reproducibly, so that it can be precisely matched to the knitted material to be processed and the machine operating speed. Central pressure control via electrical output and electrical monitoring of the status of the monitors allows the units to be connected to an electronic program control system.

Description of the function of the thrust force detector in the thread.

By threading the needle, the yarn V extends, for example, from the brake on the creel of the circular knitting machine, through an inlet guide located at the narrower side of the chamber 1 of rectangular cross section and an outlet guide hole on the front side of the chamber 1. The thread N is passed through both holes in the exemplary embodiment by displacing a part of the wider side of the front part of the chamber 1. The low-pressure gaseous medium is fed into the chamber 1 via the flange 2 located in the front part of the chamber 1 into the rear of the chamber 1. For safe

231 367 catching the thread N into the catch 8 on the guide element ^ee briefly introduces the gaseous medium from the high pressure distribution system into the element χ for a short time, for example by means of a nozzle connected to the high pressure distribution hose. The element χ has a cavity in the form of a baffle collector which allows the flow of air to the rear of the chamber 1, opens the unidirectional valve 6 and exerts pressure on the back face of the guide element 6 made of a lightweight material. The guide element 8 is pushed into the front of the chamber 1 and the catch 8 terminated by a suitably shaped hook for securely engaging the thread V is thus caught in the space between the inlet and the outlet opening through which the thread N is drawn. For interruption of the compressed air flow to the nozzle, the guide element 8 with the catch 8 and the threaded thread E is pushed by the low-pressure medium into the working position, i.e. into the rear part of the chamber 1 beyond the opening of the pneumatic sensor χ by means of a diaphragm. 11 ee opens contacts 12 of sensor χ. The movement of the guide element 6 into the working position is inhibited by a one-way leakage valve 6, which imposes a large flow resistance of the gaseous medium when the guide element 6 moves to the working position. When moving in the opposite direction of the guide element 6, i.e. from the working position when the supply loop is shortened, the unidirectional valve 6 has a low flow resistance. In the sense of the invention, the working position ae is understood to mean the position of the guide element 6 during the operation of the knitting machine, i.e. when knitting, in which the yarn N forms in the chamber 1 a supply loop between the inlet and outlet openings.

In the case of a failure in the yarn supply system N, for example, in a pull-out due to a poorly drawn thread on the bobbin, the guide element 8 is pulled from the rear of the chamber 1 towards the front, thereby gradually reducing the length of the stock loop. By moving the guide element 6 in the chamber 1 towards its front part, the pressure of the gaseous medium on the sensor 11 membrane is interrupted, thereby connecting the contacts 12 and sending a pulse for further processing.

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- 8 which may be to stop the machine with a fault location signal or to switch the machine to low speed. In the case of spontaneous resolution of snags, which often occurs during knitting, the length of the stock loop again extended, it moves the guide element 2 in the working position and the contacts 12 operated diaphragm sensor ² ® ° Five disconnects · Figures · 1 unillustrated control system and switches the machine back to working speed. A fault in the yarn supply system is indicated by the flashing light, in the exemplary embodiment by LED 14. This is located at the front wall of the chamber 1.

In an exemplary embodiment, one of the electrical contacts is realized by a metallic conductive coating on the inside of the membrane 11. The other electrical contact 12 is then a printed circuit with an etched motif.

The force acting on the guide element ^and £ mediated overpressure gaseous medium is variable, depending on the position of the guide element £ in the chamber 1. The automatic control of the force takes place via non-return valve. As the guide element 6 moves away from the operating position, the force exerted on the guide element 5 by the pressure of the gaseous medium increases. The pressure of the gaseous medium supplied to the chamber 1 remains constant.

The guide pin 15 serves to facilitate the introduction of the thread N into the catch 8 on the guide element 8 and the thread guide pin 10 for thread guide.

N. The stop pins 17, 19 are intended to limit the extreme positions of the guide element 4.

Claims (8)

OBJECT OF THE INVENTION 231 367 1 · A method of ensuring reliable operation of the knitting machine by eliminating the malfunctions occurring in the yarn supply system from spools to knitting needles, enabling the malfunction to be signaled and stopped or switched to slow speed to eventually resume working speed if the malfunction resolves a yarn supply loop through the action of a pressurized gaseous medium to absorb the tensile force shocks in the yarn during operation of the knitting machine, characterized in that the length of the yarn supply loop is sensed and held within predetermined limits by the pressurized gaseous medium; the thread, which force causes the action of the impact monitor, the breaking force is only compensated for by the directive component of the response to this breaking force, whereas the directive component of the reaction exhibits a constant value, centrally adjustable pressure and gaseous medium pressure · 2. A yarn tensile force detector for performing a method of ensuring reliable operation of a knitting machine according to item 1, comprising a chamber having an inlet and an outlet for the yarn, a pressurized medium supply, a guide element displaceable in the chamber and equipped with a yarn tensioning catch and a signaling lamp, characterized in that the chamber (1) is provided with a flange (2) for supplying a low pressure gaseous medium, a sensor ( 3) the position of the guide element (4), at least one dirt collecting chamber (5), means (6) for slowing the movement of the guide element (4) in the chamber (1) as the storage loop length is shortened and the suspension element (7) threads into the catch (8) provided on the guide element (4) by means of a pressurized gaseous medium · 231 367 - 10 3. The storage monitor according to claim 2, characterized in that the flange (2) for supplying the low-pressure gaseous medium is located in the front part of the chamber (1). The storage monitor according to claim 2, characterized in that the position sensor (3) of the guide element (4) is formed by at least two electrical contacts (12) actuated pneumatically by a diaphragm (11). Cartridge monitor according to claim 4, characterized in that one of the electrical contacts (12) is formed as an inner metal coating of the membrane (11) and the other or further electrical contact (12) forms a printed circuit with an etched motif. Cartridge monitor according to claim 2, characterized in that the dirt collection chamber (5) is located in the rear part of the chamber (1) below the catch hook (8) and closed with a full lid (9) or a perforated lid. The container monitor according to claim 2, characterized in that the means (6) for slowing the movement of the guide element (4) is a one-way valve. Cartridge watcher according to claim 2, characterized in that the thread-fixing element (7) is mounted on the rear of the chamber (1), the flange (10) of the thread-fixing element (7) in the thread-catching element (7). 8) form a bearing surface for the means (6) for slowing the movement of the guide element (4) in the chamber (1);