CH715390A1 - Method for operating a ring spinning machine. - Google Patents

Abstract

A method for operating a ring spinning machine (1) with a maintenance carriage (14) is disclosed, the ring spinning machine (1) having a large number of spinning stations (2), the spinning stations (2) being a drafting unit (5) with an outlet cylinder, one Thread guide (7), a balloon constriction ring (8), a spindle (9), a ring traveler (13) and a spindle monitor (15), and wherein the maintenance carriage (14) along the spinning positions (2) on one side of the ring spinning machine ( 1) moved and thread breaks at the spinning positions (2) corrected by a standard program. If a thread break at a spinning station (2) is determined, a state of the spinning station (2) with the thread break is determined in a module (24 1) and, based on the determined state, a decision is made as to whether the thread break is remedied by the standard program of the maintenance carriage (14) can be. The invention also relates to a corresponding ring spinning machine (1).

Description

Technical field

The invention relates to a method for operating a ring spinning machine according to the preamble of the independent claim and to a corresponding ring spinning machine.

State of the art

Operating robots or maintenance trolleys that attach threads to a ring spinning machine after a thread break are well known. In particular, the operating robot from EP 3 94 671 A2 may be mentioned here. The latter moves along a number of spinning positions, determines thread breaks and then tries to correct the determined thread breaks. First, the belt that drives the spindle is lifted off the spindle by means of a special spindle brake device and then the spindle is stopped. An auxiliary thread is also used. One end of the auxiliary thread is attached to a winder which can be moved around the spinning cop, in order then to be wound around the spinning cop. The auxiliary thread is then threaded through the ring traveler and the thread guide and brought into the area of the exit of the drafting system. The spindle and thus also the spinning cop are then driven again and the auxiliary thread is brought into the path of the drawn roving so that it is twisted with it.

[0003] DE 3 932 727 discloses a method for eliminating a thread break on a ring spinning machine. It is provided that an auxiliary thread carried by a maintenance car is loosely placed on the bobbin of a spindle and attached to a fuse supplied by a drafting system. It is also known from DE 3 932 727 that during the work of the maintenance vehicle the spindle is actuated by an actuating element, a brake and / or the drive is interrupted.

WO 2009 132 469 relates to a ring spinning machine with a single spindle drive. The workplaces can contain sensors or other means for determining certain parameters at the workplaces. For example, the current or power consumption by the spindle drive or the spindle speed by the spindle drive electronics, if necessary by means of sensors, are recorded. Information about thread breaks or thread tension can be determined from these measurement data. The spindle in question or the drive assigned to it can be stopped autonomously in the event of a thread break by the spindle drive or section electronics unit.

The relevant spindle drive electronics unit or section electronics unit can, for example, for the autonomous execution of one or more of the following functions thread break detection, match stop, individual spindle drive control, thermal monitoring of the individual spindle drives, match change, spindle speed measurement, thread tension measurement, communication with an assigned automatic walking machine, Spinning station operator guidance, fault displays, hand switches and / or other sensor functions. A thread break and / or an increased thread tension can preferably be determined by the respective spindle drive electronics unit via the current or power consumption of the electric motor drive assigned to the respective job. The machine control unit itself carries out e.g. the start-up and / or sequence control, which can be effective, for example, both in the event of a normal shutdown and in the event of an emergency shutdown in the event of a power failure.

Regardless of a mechanical spindle brake or a single spindle with electronics, it is disadvantageous, however, that the maintenance trolley can only be used to a limited extent, since in certain constellations it is not possible for the maintenance trolley to be pieced, as is the case, for example, in EP 415 290 as irreversible thread breaks is described.

Presentation of the invention

The invention has for its object to provide a method for operating a service vehicle, with which the reliability and possible uses of the service vehicle can be increased.

According to the invention the object is achieved by a method for operating a ring spinning machine with a maintenance car according to the preamble of the independent method claim in that a state of the spinning position is determined with the thread break, and a decision is made based on the determined state whether the Thread breakage can be remedied by the standard program of the maintenance trolley.

Advantageously, if it is determined that the determined state of the spinning station does not allow the thread break to be eliminated by the standard program, the maintenance vehicle does not operate the spinning station. Alternatively, the maintenance trolley can move to the spinning station and determine the condition of the spinning station. This avoids unnecessary attempts to fix a thread break.

Advantageously, the ring spinning machine can be informed of the determined state of the spinning station, this can be shown on a display and / or an operator can be called to put the spinning station back into operation.

The spinning station can advantageously be monitored by a camera, a microphone, a capacitive sensor, the spindle monitor and / or a thread and sliver monitor, the result transmitted to the module and the state is determined in the module. Alternative means for the same purpose are also conceivable.

The spinning station can advantageously be recorded by at least one camera and the state of the spinning station can be determined by image analysis. It is possible to record the spinning station in sections from different cameras, to transmit the result to the module and to determine the state in the module. It is advantageous if the recorded state images are stored and used in the image analysis of the state of the spinning station. The accuracy of the condition analysis during operation can be improved by presenting and demonstrating real examples of conditions in a kind of training session. This is particularly advantageous if a ring spinning machine is converted or converted and the conditions at the spinning positions have changed. This training can advantageously improve the quality or speed of the condition analysis. The module can also contain self-learning functions so that the condition analysis can adjust to changing environmental conditions such as production speed (delivery, speed), thread color, lighting, etc.

[0013] At least one of the following states is advantageously determined in which the thread break cannot be remedied by the standard program of the maintenance vehicle: the roving bobbin is empty or the roving feed is interrupted; there is a wrap on the outlet cylinder; a standing thread is between the outlet cylinder and thread guide; a dirty thread guide); there is no sleeve; there is no spindle; a dirty or missing ring traveler; or unknown interfering objects.

[0014] The maintenance trolley or a cleaning trolley can advantageously carry out at least one of the following actions before the thread break is rectified clean a ring traveler or insert a new ring traveler; remove a standing thread; remove a wrap; or trigger a match stop.

The maintenance trolley and / or the ring spinning machine can advantageously be retrofitted with the module for determining the state.

According to the invention the object is also achieved by a ring spinning machine with a maintenance trolley according to the preamble of the independent device claim in that a module is present to determine the state of the spinning station and, on the basis of the determined state, to determine whether the thread breakage is caused by the standard program of the Maintenance car can be fixed.

The module can advantageously be designed to inform the ring spinning machine about the state of the spinning station, to display the state on a display and / or to call an operator.

Advantageously, there can be at least one camera, at least one microphone, at least one capacitive sensor, the spindle monitor and / or at least one thread and sliver monitor, which are connected to the module in order to determine the state of the spinning station.

[0019] A memory can advantageously be present in order to store state images and comparison images recorded with a camera and to use them in an image analysis of the state of the spinning station.

[0020] The module can advantageously determine at least one of the following states in order to determine the state of the spinning station: the roving bobbin is empty or the roving feed is interrupted; there is a wrap on the outlet cylinder; a standing thread is between the outlet cylinder and thread guide; a dirty thread guide; there is no sleeve; there is no spindle; a dirty ring traveler; or unknown interfering objects.

[0021] The maintenance trolley and / or the ring spinning machine can advantageously be retrofitted by the status detection module.

Configurations are advantageously excluded by the present invention in which piecing by the maintenance vehicle is not possible. The reliability and possible uses of the maintenance cart can thus advantageously be increased.

Brief description of the figures

[0023] Further advantages of the invention are described in the following exemplary embodiments, wherein <tb> Fig. 1 <SEP> a ring spinning machine with a maintenance trolley; <tb> Fig. 2 <SEP> a detailed drawing with a maintenance car in front of a spinning station; and <tb> Fig. 3 <SEP> a flow chart of the method according to the invention, <tb> shows. The same features are provided with the same reference symbols in different figures.

Ways of Carrying Out the Invention

1 schematically shows a ring spinning machine 1 according to the invention, which has a large number of spinning stations 2 arranged next to one another. The spinning stations 2 are arranged in a longitudinal direction x of the ring spinning machine 1 between a head 31 and a foot 32. Head 31 and foot 32 of the ring spinning machine 1 can contain bearings, drives, controls, etc., which are necessary for the operation of the machine. As can further be seen, for example, at two spinning stations 2 shown schematically in FIGS. 1 and 2, each spinning station 2 consists of at least one roving spool 4, which is arranged above a drafting device 5 and on which a roving 6 is wound. The roving 6 runs from the roving spool 4 through the drafting unit 5, where it is stretched, in order to then be guided to a yarn-forming element via a thread guide 7 and a balloon constriction ring 8. On a ring bench 11 there is a ring with holder 12 which carries a ring traveler 13. The rotating ring traveler 13 winds the finished yarn on a sleeve 10. The sleeve 10 is placed on a spindle 9. A maintenance carriage 14 moves along the ring spinning machine 1, which in the event of a yarn break breaks to a corresponding spinning station 1 and automatically corrects the yarn break. The individual spinning stations 2 can be equipped with spindle monitors 15 or other sensors for monitoring the ring traveler 13 and / or the thread run in order to detect a thread break. Alternatively or additionally, the spinning stations 2 can be equipped with individual spindle drives.

Fig. 2 shows schematically a spinning station with a maintenance carriage 14 located in front of the spinning station. The maintenance carriage 14 comprises a controller 16 and a memory 160, which can be part of the controller 16 or separate from it. The main control 16 uses a standard program to control the operation of the maintenance carriage 14 for the automatic removal of a broken thread. The maintenance carriage 14 comprises several, all or at least one of the following functional assemblies: a yarn search device 17 as disclosed in WO 2018/100 464; WO 2018/100 464 relates to a method and a device for detecting the thread end on a bobbin in a ring spinning machine that produces yarn after the interruption due to a yarn break, wherein after the yarn breakage the bobbins is approached by a suction nozzle into which the yarn end moves rotating cop is sucked. A rod and a movable slide with a carrier surface approach the surface of the cop1. The movable device moves in a different direction than the rotating cop, the yarn end being caught and pulled by the movement of the movable device, and the yarn end being conveyed to the suction nozzle; a cop lifting device 18 as described in the unpublished Czech patent application No. PV 2018-47 of January 31, 2018; the patent application relates to a bobbin lifting device for transporting a bobbin from the spindle of a spinning station of a ring spinning machine to a thread end search position; a rotor threading device 19 as described in the unpublished Czech patent application No. PV 2018-34 of January 24, 2018; the patent application relates to a device for threading yarn into a rotor on a ring with a flange at a spinning position of a ring spinning machine; a yarn handling device 20 as described in the unpublished Czech patent application No. PV 2018-48 dated January 31, 2018; the patent application discloses a yarn handling device at a spinning station of a ring spinning machine for detecting a thread end on a bobbin. The device has a suction tube with a suction opening which can be assigned to a spinning station, the suction tube being connected to a vacuum source, the suction tube being attached to a positioning system for guiding the mouth of the suction tube on a drafting device of the spinning station in order to resume the spinning process; a position device 21 as described in the unpublished Czech patent application no. PV 2018-49 from January 31, 2018 and unpublished Swiss patent application No. 01 185/17 from September 28, 2017; the positioning device 21 serves to position the maintenance carriage 14 in front of the spindle 9. a spindle brake unit 22, which is similar or similar to the disclosure of EP 394 671, wherein the brake shoe 246 can be replaced by a roller; a display 23 for displaying and entering data; a module 241 for determining the state of a spinning station 2.

All of the disclosures mentioned in patent applications for parts of the maintenance cart 14 are integral parts of the present description. Communication within the maintenance cart 14 is shown by a dotted line. The maintenance trolley can integrate all parts or only individual functions. 3 shows in parallel a flow chart of the method according to the invention.

If a thread break is determined (Fig. 3, step 100), the standard program for re-spinning provides that the maintenance carriage 14 searches for the thread end on the bobbin and leads through the balloon constriction ring 8 and thread guide 7 to the drafting system 5 and starts there.

If a thread break is now determined at a spinning station 2 (FIG. 3, step 100), the state of the spinning station 2 is determined by module 241 and / or a corresponding module 242, which is located on the ring spinning machine 1 (FIG. 3, step 200) to determine whether the thread break can be remedied by the maintenance carriage 14 using the automated program mentioned.

The following could be determined by module 241 and / or module 242 as possible states in which automatic thread breakage elimination by the above-mentioned components is difficult or impossible: the roving spool 4 is empty or the roving feed is interrupted; a winding is located on the outlet cylinder of the drafting device 5; a standing thread is between the outlet cylinder and thread guide 7; a dirty thread guide 7; there is no sleeve on the spindle 10; there is no spindle 10; a dirty or missing ring traveler 13 or unknown interfering objects.

The state of the spinning station 2 could be determined by a camera 25, a microphone 26, a capacitive sensor 27, by the spindle monitor 15 and / or a thread and sliver monitor or another equivalent sensor.

In a first variant, the maintenance carriage 14 or the ring spinning machine 1 comprises one or more cameras 25 which take one or more pictures of the spinning station. It is also conceivable, as shown in FIG. 2, that several cameras are used, for example an upper camera, which takes up the roving bobbin 4 and drafting device 5, a camera in the middle for thread guide 7 and balloon constriction ring 8 and a camera below for spindle 9, cops 10, ring 12 and ring traveler 13. The captured images are processed in module 241 and / or module 242 for status detection. Different operating states at the spinning station are then recognized with appropriate pattern recognition algorithms and example or comparison images. A running spinning station with no problem when piecing could serve as a comparison image, or images with corresponding states that need to be determined. Many of the above conditions can be determined by image recognition.

In a second variant, the state, for example a winding on the outlet cylinder, is determined by a capacitive sensor 26. The ring spinning machine 1 is equipped with a controller 50 and a memory 500, which can be part of the controller 50 or can be separated from it. In the present example, the ring spinning machine 1 includes the module 242 for status detection in addition to the maintenance trolley. The sensor 26 is read out by the module 242 and the sensor 26 sends the corresponding measurement data. The module 242 then recognizes, for example, that there is a winding on the outlet cylinder of the drafting unit 5.

In a third variant, the state is determined by a microphone 27. Changes in one of the familiar noises during the spinning process can indicate one of the above-mentioned conditions. The microphone 27 is read by the module 242 and sends the corresponding measurement data. Module 242 then recognizes one of the above conditions.

In a fourth variant, the state is determined by a spindle monitor 15. In particular, it could be recognized whether a ring traveler 13 is present and whether it is dirty.

In a fifth variant, the condition is determined by a thread and sliver monitor. For example, this could recognize a standing thread.

It goes without saying that the variants mentioned can be used and evaluated side by side and also in combination. It is entirely possible that module 242 of the ring spinning machine 1 determines (FIG. 3, decision step 300) that the standard program of the maintenance carriage 14 does not enable the yarn break to be eliminated (FIG. 3, step 400, left path from step 300). In this case, the maintenance carriage 14 can omit the corresponding spinning station 2 and does not have to move to it. If no such condition of unrecoverable thread breakage is found, the thread breakage is remedied in the predetermined manner (FIG. 3, step 500, right path from step 300).

It is also possible for the maintenance carriage 14 to move to the spinning station 2 and for the module 241 to check whether a corresponding condition is present. This is possible, for example, if there is no such module 242 on the ring spinning machine 1. If the module 241 does not find that the thread break cannot be remedied, the thread break is automatically remedied by the above-mentioned components of the maintenance carriage 14 using the standard program mentioned.

If a condition is determined and it is recognized that it is not possible to fix the thread break at the spinning station 2 by means of the above-mentioned program of the maintenance carriage 2, the maintenance carriage 2 will not attempt to remedy the thread break. The spinning position could be indicated on the spindle monitor 15 by an LED, etc. The maintenance carriage 14 could then inform the ring spinning machine 1 about the spinning station 2 and the type and scope of the determined state. The communication between the maintenance carriage 14 and the control of the ring spinning machine 1 is shown by a dashed arrow. The ring spinning machine 1 will enter this information into a central data information system of the spinning mill and could display it on a display 51. The information can advantageously contain information about which service personnel or which operator / technician with which skills is necessary to put the spinning station 2 into operation again. A corresponding operator could be called via a mobile device 15 (smart watch, smart phone, tablet, etc.). The mobile device 15 could be connected to the ring spinning machine 1 or the higher-level, central data information system of the spinning mill via a mobile radio network or a local connection (NFC, WLAN, ZigBee, etc.).

The accuracy of the condition analysis during operation can be improved by presenting and demonstrating real examples of conditions to the maintenance car. This is particularly advantageous if a ring spinning machine is converted or converted and the conditions at the spinning positions have changed. This training can advantageously improve the quality or speed of condition analysis. The module 241, 242 can contain self-learning functions, so that the condition analysis can adjust to changing environmental conditions such as production speed (delivery, speed), thread color, lighting, etc.

In a further exemplary embodiment, if a condition is ascertained that the thread break cannot be eliminated with the standard program, the maintenance trolley could carry out at least one of the following actions before the thread break is removed: clean a ring traveler or insert a new ring traveler; remove a standing thread; remove a wrap; trigger a match stop and reset a triggered match stop.

[0041] This presupposes that the maintenance carriage 14 is capable of such an activity. A suction device could, for example, remove a winding or gripper, brushes a standing thread.

In another exemplary embodiment, a second maintenance or cleaning trolley could take over the abovementioned activities for eliminating the undesirable conditions. As soon as one of the abovementioned conditions is determined by the ring spinning machine 1 or the maintenance carriage 14, the second maintenance carriage (cleaning carriage) will control the spinning station and remove the condition and prepare the spinning station in order to be spun on by the maintenance carriage 14. The second maintenance or cleaning trolley could also take over the entire functionality of the status determination by the module 241, so that the maintenance trolley 14 always encounters spinning positions that can be spun on.

The maintenance carriage 14 and / or the ring spinning machine 1 could be retrofitted with the sensors (camera, microphone, capacitive sensor, thread and sliver monitor, etc.) and an additional module for determining the condition or with the cleaning carriage.

Configurations are advantageously excluded in which piecing by the maintenance car is not possible. The reliability and possible uses of the maintenance cart can thus advantageously be increased.

Reference list

[0045] <tb> 1 <SEP> ring spinning machine <tb> 2 <SEP> spinning positions <tb> 31 <SEP> head of ring spinning machine 1 <tb> 32 <SEP> foot of the ring spinning machine 1 <tb> 4 <SEP> roving spool <tb> 5 <SEP> drafting system <tb> 6 <SEP> roving <tb> 7 <SEP> thread guide <tb> 8 <SEP> balloon constriction ring <tb> 9 <SEP> spindle <tb> 10 <SEP> sleeve <tb> 11 <SEP> ring holder <tb> 12 <SEP> ring bench <tb> 13 <SEP> ring traveler <tb> 14 <SEP> maintenance car <tb> 15 <SEP> spindle monitor <tb> 16 <SEP> control <tb> 160 <SEP> memory <tb> 17 <SEP> yarn search device <tb> 18 <SEP> bobbin lifting device <tb> 19 <SEP> rotor threading device <tb> 20 <SEP> yarn handling device <tb> 21 <SEP> position device <tb> 22 <SEP> spindle brake unit <tb> 23 <SEP> display <tb> 241 <SEP> module for condition determination (maintenance car 14) <tb> 242 <SEP> module for status determination (ring spinning machine 1) <tb> 25 <SEP> camera <tb> 26 <SEP> capacitive sensor <tb> 27 <SEP> microphone <tb> 50 <SEP> Control of the ring spinning machine 1 <tb> 500 <SEP> control <tb> 51 <SEP> Display of the ring spinning machine 1 <tb> 52 <SEP> Mobile device <tb> <SEP> <tb> 100 <SEP> detection of a thread break <tb> 200 <SEP> condition analysis <tb> 300 <SEP> decision whether it is possible to fix the thread break <tb> 400 <SEP> Unable to fix the thread break <tb> 500 <SEP> Start threading

Claims (17)

1. Method for operating a ring spinning machine (1) with a maintenance carriage (14), wherein the ring spinning machine (1) has a plurality of spinning stations (2), the spinning stations (2) a drafting device (5) with an outlet cylinder, a thread guide (7), a balloon constriction ring (8), a spindle (9), a ring traveler (13) and a spindle monitor (15), and wherein the maintenance carriage (14) moves along the spinning stations (2) on one side of the ring spinning machine (1) and eliminates thread breaks at the spinning stations (2) by means of a standard program, comprising the method step that is determined by a thread break at a spinning station (2) is characterized in that in a module (241, 242) a state of the spinning station (2) with the thread break is determined, and on the basis of the determined state it is decided whether the thread break can be remedied by the standard program of the maintenance carriage (14). 2. The method for operating a ring spinning machine (1) according to claim 1, characterized in that if it is determined that the determined state of the spinning station (2) does not allow the thread break to be eliminated by the standard program, the maintenance carriage (14) the spinning station (2 ) does not start. 3. A method for operating a ring spinning machine (1) according to claim 1, characterized in that maintenance cars (14) move to the spinning station (2) and the state of the spinning station (2) is determined. 4. A method for operating a ring spinning machine (1) according to one of the preceding claims, characterized in that the ring spinning machine (1) is informed of the determined state of the spinning station (2), is displayed (23, 51) and / or an operator is called to put the spinning station (2) into operation again. 5. Method for operating a ring spinning machine (1) according to the preceding claim, characterized in that the spinning station (2) by a camera (25), a microphone (27), a capacitive sensor (26), by the spindle monitor (15) and / or a thread and sliver monitor is monitored, the result is transmitted to the module (241, 242) and the state in the module (241, 242) is determined. 6. A method for operating a ring spinning machine (1) according to one of the preceding claims, characterized in that the spinning station (2) is recorded by at least one camera (25) and the state of the spinning station (2) is determined by image analysis. 7. The method for operating a ring spinning machine (1) according to the preceding claim, characterized in that the spinning station (2) is recorded in sections by different cameras (25), the result is transmitted to the module (241, 242) and the state in the Module (241, 241) is determined. 8. A method for operating a ring spinning machine (1) according to the preceding claim 6 or 7, characterized in that recorded state images are stored and used in the image analysis of the state of the spinning station (2). 9. A method for operating a ring spinning machine (1) according to the preceding claim, characterized in that the maintenance car (14) before or during operation examples of conditions are presented to improve the quality or speed of the condition analysis. 10. A method for operating a ring spinning machine (2) according to one of the preceding claims, characterized in that at least one of the following conditions is determined in which the thread break cannot be remedied by the standard program of the maintenance carriage (14): - The roving spool (4) is empty or the roving feed is interrupted; - There is a wrap on the outlet cylinder; - A standing thread is between the outlet cylinder and thread guide (7); - a dirty thread guide (7); - There is no sleeve (10); - There is no spindle (9); - a dirty or missing ring traveler (13); - or unknown interfering objects. 11. A method for operating a ring spinning machine (1) according to one of the preceding claims, characterized in that the maintenance carriage (14) or a cleaning carriage carries out at least one of the following actions before the thread break is eliminated - Clean a ring traveler (13) or insert a new ring traveler (13); - remove a standing thread; - remove a wrap; or - trigger a match stop. 12. A method for operating a ring spinning machine (1) according to one of the preceding claims, characterized in that the maintenance carriage (14) and / or the ring spinning machine (1) are retrofitted with the module (241, 242) for determining the state. 13. Ring spinning machine (1) with a maintenance carriage (14), wherein the ring spinning machine (1) has a plurality of spinning stations (2), the spinning stations (2) a drafting device (5) with an outlet cylinder, a thread guide, a balloon constriction ring (8), a spindle (9), a ring traveler (13) and comprises a spindle monitor (15), wherein the maintenance carriage (14) is arranged to be movable along the spinning stations (2) on one side of the ring spinning machine (1) and can repair thread breaks at the spinning stations (2) with a standard program, characterized in that a module (241, 242) is present in order to determine the state of the spinning station (2) and, on the basis of the determined state, ascertains whether the thread break can be remedied by the standard program of the maintenance carriage (2). 14. Ring spinning machine (1) according to the preceding claim, characterized in that the module (241, 242) is designed to inform the ring spinning machine (1) about the state of the spinning station (2), the state on a display (23, 51) and / or to call an operator. 15. Ring spinning machine (1) according to one of the preceding claims 13 or 14, characterized in that at least one camera (25), at least one microphone (27), at least one capacitive sensor (26), the spindle monitor (15) and / or at least a thread and sliver monitor is present and is connected to the module (241, 242) in order to determine the state of the spinning position (2). 16. Ring spinning machine (1) according to one of the preceding claims 13 to 15, characterized in that a memory (160) is present in order to store state images and comparison images recorded with a camera (25) and in an image analysis of the state of the spinning station (2 ) to use. 17. Ring spinning machine (1) according to one of the preceding claims 13 to 16, characterized in that at least one of the following states can be determined by the module (241, 242) in order to determine the state of the spinning station (2): - The roving spool (4) is empty or the roving feed is interrupted; - There is a wrap on the outlet cylinder; - A standing thread is between the outlet cylinder and thread guide (7); - a dirty thread guide (7); - There is no sleeve (10); - There is no spindle (9); - a dirty ring traveler (13); - or unknown interfering objects.