Threading device of flat knitting machine

Abstract

A threading device of a flat knitting machine comprises a support and a needle plate arranged on the support, and is characterized in that a wire feeding mechanism is arranged on the support and comprises a closed-loop motor used for driving a steel wire to perform threading action, and a drive control plate is arranged on the closed-loop motor and used for driving the closed-loop motor and obtaining a current feedback signal of the closed-loop motor; a wire guide pipe matched with the wire feeding mechanism is arranged at the end of the support. Compared with the prior art, load change (namely resistance change) in the threading process can be dynamically sensed through current signals fed back by the closed-loop motor in real time and the driving control board integrated on the closed-loop motor, and when resistance is abnormally increased (such as wire blockage precursor) or suddenly reduced (such as steel wire breakage or separation), the system can immediately recognize the resistance through the current change, so that the safety of the threading process is ensured. And the output torque of the motor is adjusted in real time or protection measures such as stopping are taken, so that real-time and foresight detection and protection of wire blocking and wire breaking faults are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of computerized flat knitting machines, and in particular to a flat knitting machine thread insertion device. BACKGROUND

[0002] A computerized flat knitting machine is a highly automated knitting equipment. The "starting bottom" or "starting course" is a key step in the knitting process to form the first course of fabric. To achieve this step, modern computerized flat knitting machines generally use a starting bottom plate (or thread insertion plate) device with a steel wire (also known as a locking wire or steel thread). The basic working principle is as follows: at the beginning of knitting, a specially designed steel wire is inserted into the starting course needle of the starting bottom plate through a set of devices, which hooks the yarn to provide initial pulling force and forms a stable starting bottom loop; after knitting to a certain stage, the steel wire is pulled out of the fabric to continue subsequent knitting.

[0003] Currently, the device that realizes the functions of steel wire insertion and extraction is the core component of the automatic starting bottom plate system. There are many related devices disclosed in the prior art, which are mainly aimed at realizing the automation of insertion / extraction to replace the early tedious manual operation, thereby improving the production efficiency and stability.

[0004] A common technical solution is to use an independent "steel wire insertion and extraction device". This device is usually driven by a motor (stepping motor or servo motor) through a transmission mechanism such as a synchronous belt and a gear, which pushes the steel wire to make a straight reciprocating motion, thereby completing the actions of insertion into the starting course needle and extraction. For example, some solutions set a special steel wire insertion and extraction device below the thread insertion plate, and set a limit switch or inductor on the steel wire path, which triggers a signal when the steel wire moves to a specific position to control the motor to stop, thereby achieving precise control of the stroke. Another idea is to design an integrated "steel wire insertion and extraction device", which usually includes a steel wire insertion driving mechanism and a steel wire extraction driving mechanism, and a steel wire detection inductor assembly is arranged between the two mechanisms to monitor the running state by detecting the change of the tension of the steel wire, so as to alarm in time when a fault occurs.

[0005] Chinese Patent Application No. 201922292346.4 discloses a bottom plate structure for a computerized flat knitting machine. This structure includes a bottom plate body with several guide combs evenly spaced on it. Each guide comb has concentric threading holes. A long pressure plate is connected to the front of the bottom plate body, and an assembly groove is formed between the right side of the long pressure plate and the bottom plate body. A left support plate is connected to the left side of the bottom of the bottom plate body, and a linkage is connected to the left support plate. A right support plate is connected to the right side of the bottom of the bottom plate body. Chinese Patent Application No. 202010960913.3 discloses an automatic wire threading device. This device ensures stable and reliable wire threading by unidirectionally driving the take-up and threading gears via a motor, guaranteeing the stable and reliable operation of the flat knitting machine. It includes a frame, on which a set of threading plates are provided on the upper crossbeam. The threading needles of the threading plates are provided with through threading holes, and the threading holes of all the threading needles are arranged in a straight line. A guide threading plate is provided on one side of the upper crossbeam of the frame. A guide threading channel is provided on the outer periphery of the guide threading plate. A drive mounting frame is provided in the lower area of ​​the frame corresponding to the guide threading plate. A drive mounting frame is provided with a drive motor, a take-up reel, and a thread pressing roller. The output end of the drive motor is connected to a drive shaft. A first one-way bearing and a second one-way bearing are sleeved on the drive shaft. The first one-way bearing and the second one-way bearing rotate in opposite directions.

[0006] Existing main control methods mostly adopt an architecture of "control board + open-loop stepper motor + multiple sensors (wire breakage / blockage sensor, zero position sensor, and position sensor)," which leads to complex wiring, a large number of sensors, cumbersome installation and debugging, and sensors that are prone to damage or sensitivity mismatch, affecting the long-term stable operation of the system. Furthermore, traditional wire blockage / breakage detection relies on physical contact sensors, which can only trigger a signal when the wire is completely blocked or broken, resulting in a serious detection lag. This can easily lead to excessive wear, bending, or even breakage of the wire during forced threading, severely affecting the wire's lifespan and threading success rate. Summary of the Invention

[0007] The present invention aims to overcome the defects in the prior art and provide a flat knitting machine threading device with a simpler structure, more intelligent control, more reliable operation, and real-time and forward-looking protection against wire blockage or wire breakage.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: a flat knitting machine threading device, comprising a support and a needle plate disposed on the support, characterized in that the support is provided with a threading mechanism, the threading mechanism comprising a closed-loop motor for driving the steel wire to perform threading action, the closed-loop motor being provided with a drive control board for driving the closed-loop motor and acquiring its current feedback signal; the end of the support is provided with a guide tube that cooperates with the threading mechanism.

[0009] As a preferred scheme of the present application, the drive plate adjusts the output torque of the closed-loop motor in real time according to current change during the wire threading process.

[0010] As a preferred scheme of the present application, the closed-loop motor is provided with a rear cover for covering the drive plate, and a motor wire pressing cover is arranged on one side of the closed-loop motor.

[0011] As a preferred scheme of the present application, the support is provided with a wire winding disc, the wire winding disc is provided with a driven gear, and the output end of the closed-loop motor is provided with a driving gear engaged with the driven gear.

[0012] As a preferred scheme of the present application, a zero position sensor for detecting the initial position of wire threading is further included, and the zero position sensor is arranged at the outlet of the wire winding disc.

[0013] As a preferred scheme of the present application, the support is provided with a wire feeding wheel assembly, the wire feeding wheel assembly includes two first wire feeding wheels and two second wire feeding wheels, and the wire passes between the two first wire feeding wheels and the two second wire feeding wheels.

[0014] As a preferred scheme of the present application, the two first wire feeding wheels are each provided with a first gear, the two first gears are engaged with each other, and one of the first gears is engaged with the driving gear.

[0015] As a preferred scheme of the present application, the two second wire feeding wheels are each provided with a second gear, the two second gears are engaged with each other, and one of the second gears is engaged with the driving gear.

[0016] As a preferred scheme of the present application, the needle plate is provided with a plurality of threading needles arranged along the length direction of the needle plate, the plurality of threading needles are each provided with a threading hole, and the plurality of threading holes are coaxially arranged.

[0017] As a preferred scheme of the present application, the guide tube is arranged in an arc shape, and the outlet end of the guide tube is arranged opposite to the threading hole.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1. Through the current signal of the real-time feedback of the closed-loop motor, the drive control board integrated thereon can dynamically perceive the load change (i.e. resistance change) in the threading process, when encountering abnormal increase of resistance (such as precursor of wire blocking) or sudden decrease (such as wire breakage or disengagement), the system can immediately identify through the current change, and adjust the output torque of the motor in real time or take protective measures such as stopping, realizing real-time and forward-looking detection and protection of wire blocking and wire breakage faults, completely changing the lag situation of the traditional scheme relying on physical sensors to alarm only after the fault occurs completely, effectively avoiding the excessive wear, bending or breakage of the steel wire due to forced driving, greatly prolonging the service life of the steel wire, and improving the safety of the threading operation;

[0020] 2. By adopting the "closed-loop motor integrated with drive control board" as the core driving and control unit, the complex combination of "independent control board + open-loop stepping motor + multiple functional sensors (such as home, wire blocking / breaking sensor)" in the prior art is replaced, which greatly reduces the number and complexity of external sensors, fundamentally reduces the risk of system failure caused by sensor damage, sensitivity adjustment or line failure, makes the electrical structure of the whole device more simple and reliable, and significantly improves the long-term operation stability;

[0021] 3. Further, the closed-loop motor itself has precise position and speed control capability, combined with the accurate positioning of the initial position by the zero position sensor, the accuracy of the threading stroke is ensured. The arc-shaped guide tube outlet is accurately aligned with the coaxially arranged threading hole on the needle plate, providing a stable and accurately guided movement path for the steel wire. These designs together ensure that the steel wire can reliably pass through all the threading needles, improving the one-time success rate of the threading action;

[0022] 4. Further, by driving the steel wire winding disc and the meshing transmission wire feeding wheel assembly with the driving gear, power concentration and synchronization are realized, the wire feeding wheel assembly adopts the design of opposite synchronous rotation by gear meshing, ensuring that the steel wire is pushed smoothly and linearly without slipping or twisting. Combined with the accurate positioning of the initial reference by the zero position sensor and the inherent high precision control capability of the closed-loop motor, the accuracy of the threading stroke and action is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of the present application;

[0024] Figure 2 is a structural schematic diagram of the wire feeding mechanism of the present application;

[0025] Figure 3 is an exploded view of the closed-loop motor;

[0026] Figure 4 is a structural schematic diagram of the threading needle

[0027] Reference numerals: 1. Bracket; 2. Needle plate; 201. Threading needle; 2011. Threading hole; 3. Wire feeding mechanism; 301. Closed-loop motor; 3011. Drive control board; 3012. Drive gear; 3013. Rear cover; 3014. Motor wire pressing cover; 302. Zero position sensor; 303. Wire feeding wheel assembly; 303. First wire feeding wheel; 3031. Second wire feeding wheel; 3032. First gear; 3033. Second gear; 3034. Wire guide tube; 4. Steel wire; 5. Steel wire winding disc; 6. Driven gear; 601. Detailed Implementation

[0028] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] like Figures 1-4 As shown, a flat knitting machine threading device includes a support 1 and a needle plate 2 disposed on the support 1. The support 1 is characterized by having a thread feeding mechanism 3, which includes a closed-loop motor 301 for driving the steel wire 5 to perform threading action. The closed-loop motor 301 is provided with a drive control board 3011 for driving the closed-loop motor 301 and acquiring its current feedback signal. The end of the support 1 is provided with a guide tube 4 that cooperates with the thread feeding mechanism 3.

[0030] The wire feeding mechanism 3 is the core drive and control component of the device, mounted on the bracket 1. Its core is a closed-loop motor 301, which features an integrated drive and control board 3011. The drive and control board 3011 not only drives the closed-loop motor 301 but, more importantly, collects and processes the current feedback signal during motor operation in real time. By using the closed-loop motor 301 with an integrated drive and control board 3011 as the drive and control core, a highly integrated and intelligently sensing system is constructed. This fundamentally changes the traditional complex and fragile architecture relying on "independent control board + open-loop motor + multiple sensors," greatly simplifying electrical connections, reducing failure points, and improving the overall system reliability. Simultaneously, the current feedback from the closed-loop motor 301 provides a data foundation for real-time monitoring of the wire's movement, creating conditions for intelligent fault prediction and protection. The guide tube 4 ensures a smooth and accurate transition of the wire 5 from the wire feeding mechanism 3 to the needle plate 2.

[0031] The drive control board 3011 adjusts the output torque of the closed-loop motor 301 in real time according to the current change during the threading process, realizing adaptive flexible control and real-time fault diagnosis of the threading process. By analyzing the current feedback in real time, the drive control board 3011 can accurately perceive the movement resistance of the steel wire 5: when the resistance abnormally increases (such as blocked wire), the torque can be immediately increased to try to overcome it, or an alarm can be triggered to avoid hard damage; when the resistance suddenly decreases (such as wire breakage), the machine can be immediately stopped. This realizes millisecond-level and forward-looking response to faults such as blocked wire and broken wire, effectively prevents the bending, breaking or excessive wear of the steel wire 5 due to overload, and significantly improves the threading success rate and service life of the steel wire 5.

[0032] The closed-loop motor 301 is provided with a rear cover 3013 for covering the drive control board 3011, and the closed-loop motor 301 is provided with a motor wire pressing cover 3014 on one side. The rear cover 3013 covers the outside of the drive control board 3011, which plays a role in dustproof and anti-collision. The closed-loop motor 301 is provided with a motor wire pressing cover 3014 on one side, which is used to arrange and fix the power supply and signal cable, thereby improving the reliability. The rear cover 3013 provides physical protection for the integrated drive control board 3011, effectively preventing flying dust, dust and oil stains in the workshop environment from invading, and ensuring the long-term stable work of electronic components. The motor wire pressing cover 3014 standardizes and fixes the motor lead, preventing the line from loosening, wearing or interfering with each other in vibration. The two together improve the durability and anti-interference ability of the device in harsh industrial environments.

[0033] The support 1 is provided with a steel wire winding disc 6, the steel wire winding disc 6 is provided with a driven gear 601, the output end of the closed-loop motor 301 is provided with a driving gear 3012 engaged with the driven gear 601, further, the output shaft of the closed-loop motor 301 is fixed with the driving gear 3012, the support 1 is installed with the steel wire winding disc 6 for coiling and storing the steel wire 5, and the rotating shaft of the steel wire winding disc 6 is installed with the driven gear 601 which is directly engaged with the driving gear 3012. Therefore, the rotation of the closed-loop motor 301 can directly drive the steel wire winding disc 6 to perform the action of winding or unwinding the steel wire.

[0034] It also includes a zero position sensor 302 for detecting the initial position of threading. The zero position sensor 302 is located at the outlet of the steel wire winding disc 6, and further, the zero position sensor 302 is arranged at the key position where the steel wire 5 leaves the steel wire winding disc 6 and is about to enter the wire feeding wheel assembly 303. This position can most directly and accurately detect the "initial preparation state" of the steel wire 5, establishing a stable and repeatable absolute reference point for the entire threading cycle. This avoids the cumulative error that may be introduced by setting the sensor at an indirect position, further ensuring the consistency of the starting point of each threading action, thereby improving the overall action repetition accuracy.

[0035] The support 1 is provided with a wire feeding wheel assembly 303, the wire feeding wheel assembly 303 comprises two first wire feeding wheels 3031 and two second wire feeding wheels 3032, the steel wire 5 passes between the two first wire feeding wheels 3031 and the two second wire feeding wheels 3032, each of the two first wire feeding wheels 3031 is provided with a first gear 3033, the two first gears 3033 are engaged with each other, and one of the first gears 3033 is engaged with the driving gear 3012, each of the two second wire feeding wheels 3032 is provided with a second gear 3034, the two second gears 3034 are engaged with each other, and one of the second gears 3034 is engaged with the driving gear 3012.

[0036] Further, the support 1 is also provided with a wire feeding wheel assembly 303, the assembly comprises two first wire feeding wheels 3031 arranged in an up-down manner and two second wire feeding wheels 3032 arranged in an up-down manner. The steel wire 5 passes between the two pairs of wire feeding wheels. The shaft of each first wire feeding wheel 3031 is provided with a first gear 3033, and the two first gears 3033 are engaged with each other. Similarly, the shaft of each second wire feeding wheel 3032 is provided with a second gear 3034, and the two second gears 3034 are engaged with each other. The key is that one of the first gears 3033 located at the lower side and one of the second gears 3034 located at the lower side are engaged with the aforementioned driving gear 3012. This design means that the closed-loop motor 301 can synchronously drive the steel wire winding disc 6 and the first wire feeding wheel 3031 and the second wire feeding wheel 3032 through the driving gear 3012. Moreover, since the gears of each pair of wire feeding wheels are engaged, this ensures that the two wire feeding wheels arranged in an up-down manner always rotate synchronously at the same linear speed and in opposite directions, so that the steel wire 5 can be stably, non-slip and non-distorted clamped and pushed.

[0037] The needle plate 2 is provided with a plurality of threading needles 201 arranged along the length direction thereof, the plurality of threading needles 201 are each provided with a threading hole 2011, and the plurality of threading holes 2011 are coaxially arranged. Further, the support 1 serves as the mounting base of the entire device. The needle plate 2 is fixed on the support 1, and a plurality of threading needles 201 are arranged equidistantly along the length direction of the needle plate 2. Each of the threading needles 201 is provided with a threading hole 2011, and the threading holes 2011 are strictly coaxial during machining and assembly, which is the key to ensuring that the steel wire 5 can pass through smoothly at one time. It is required that the threading holes of all the threading needles are strictly coaxial. This is the most fundamental prerequisite for ensuring that the steel wire can pass through the entire row of threading needles continuously and unobstructed at one time. High-quality needle plate machining and assembly process, combined with this claim, solves the problems of threading failure or steel wire jamming caused by misalignment of needle holes in traditional devices from the "target end", directly improving the core success rate of threading operation.

[0038] The guide wire tube 4 is arranged in an arc structure, and the outlet end of the guide wire tube 4 is arranged opposite to the threading hole 2011. Further, the guide wire tube 4 is fixed at the end of the support 1, and the inlet of the guide wire tube 4 receives the steel wire 5 from the wire feeding wheel assembly 303. The guide wire tube 4 is designed as a smooth arc-shaped pipeline, and the arc curvature is optimized to minimize the friction and stress of the steel wire 5 when turning. The outlet end of the guide wire tube 4 is precisely adjusted so that the axis is aligned with the common axis of the coaxial threading holes 2011 on the needle plate 2, thereby providing perfect guidance for the steel wire 5 to enter the first threading needle. The arc-shaped guide wire tube 4 can provide a smooth and gradual curved path for the steel wire 5 sent horizontally, guiding it to turn smoothly and align with the needle plate 2, which avoids the bending, jamming or additional stress of the steel wire 5 caused by sharp turns or right-angle guides. In addition, the requirement that the outlet end is opposite to the threading hole 2011 ensures that the steel wire 5 can enter the first threading hole 2011 at the best straight angle after leaving the guide wire tube 4, laying a precise initial direction for subsequent continuous threading, thereby reducing the energy loss and direction deviation of the steel wire 5 at the end of the path, and is the last key guarantee for realizing high-precision and high-reliability threading.

[0039] The working principle and intelligent control process of the present application are as follows:

[0040] Threading preparation: when the system is initialized, the closed-loop motor 301 drives the steel wire winding disc 6 to rotate, and the steel wire 5 is retracted until the steel wire head triggers the zero position sensor 302. At this time, the steel wire 5 is in a known initial position.

[0041] Threading process: after receiving the threading instruction, the closed-loop motor 301 rotates forward. On the one hand, the steel wire winding disc 6 is driven to release a certain length of steel wire 5 through the driving gear 3012; on the other hand, the first wire feeding wheel 3031 and the second wire feeding wheel 3032 are driven to rotate in reverse synchronously through the meshing first gear 3033 and the second gear 3034, so that the steel wire 5 is stably pushed out between them. The pushed-out steel wire 5 first enters the arc-shaped guide wire tube 4, and after being guided by the guide wire tube 4, it is accurately aligned and sequentially threaded through all the coaxial threading holes 2011 on the needle plate 2, completing the threading action.

[0042] Intelligent monitoring and protection: first, sample structure data is obtained. When the closed-loop motor 301 and the steel wire 5 are installed, the threading is automatically run through the closed-loop motor 301, the corresponding current value of every 1mm is recorded, and saved to the drive control board 3011. Next time, the original sample data is compared during threading and wire retraction, including the maximum amplitude, the minimum amplitude and the average current. If the deviation of each index is too large, it is considered that the steel wire 5 is blocked.

[0043] Specifically, throughout the threading process, the integrated drive control board 3011 continuously monitors the real-time current of the closed-loop motor 301. In normal threading, the current will maintain in a relatively stable range. If the steel wire 5 encounters an obstacle in the path (such as the threading hole 2011 being slightly blocked), the resistance will increase, causing the motor current to rise. The drive control board 3011 will immediately detect this abnormal current rise, and it can take two strategies: one is to appropriately increase the torque output according to the preset algorithm, trying to overcome the resistance with a gently increased force; the second is to immediately judge as a "wire blocking" fault if the current instantaneously exceeds the safety threshold, and stop the motor and alarm quickly, thereby protecting before the steel wire 5 is forcibly bent or broken. Conversely, if the steel wire 5 is accidentally broken, the load suddenly disappears, and the motor current instantaneously drops, the drive control board 3011 can also immediately identify as a "wire breaking" fault and stop and alarm.

[0044] Wire drawing process: After threading is completed, when wire drawing is needed, the closed-loop motor 301 reverses rotation, the wire feeding wheel assembly 303 reverses rotation to pull back the steel wire 5, and at the same time the steel wire winding disc 6 winds back the steel wire 5, until the steel wire head again returns to the zero position sensor 302, preparing for the next cycle.

[0045] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application; thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0046] Although the terms: support 1, needle plate 2, threading needle 201, threading hole 2011, wire feeding mechanism 3, closed-loop motor 301, drive control board 3011, driving gear 3012, rear cover 3013, motor wire pressing cover 3014, zero position sensor 302, wire feeding wheel assembly 303, first wire feeding wheel 3031, second wire feeding wheel 3032, first gear 3033, second gear 3034, wire guide tube 4, steel wire 5, steel wire winding disc 6, driven gear 601, etc. are used more frequently in the drawings, the possibility of using other terms is not excluded. The use of these terms is only to facilitate the description and explanation of the essence of the application; any additional limitation is contrary to the spirit of the application.

Claims

1. A traversing machine threader comprising a support (1) and a needle plate (2) arranged on the support (1), characterized in that, The support (1) is provided with a wire feeding mechanism (3), the wire feeding mechanism (3) comprises a closed-loop motor (301) for driving the steel wire (5) to perform threading action, the closed-loop motor (301) is provided with a drive control board (3011), for driving the closed-loop motor (301) and obtaining current feedback signal thereof;The end of the support (1) is provided with a wire guide tube (4) matched with the wire feeding mechanism (3).

2. A traversing device for a flat knitting machine according to claim 1, characterized in that The drive control board (3011) adjusts the output torque of the closed-loop motor (301) in real time according to current change during threading.

3. A traversing device for a flat knitting machine according to claim 1, characterized in that, The closed-loop motor (301) is provided with a rear cover (3013) for covering the drive control board (3011), and one side of the closed-loop motor (301) is provided with a motor wire pressing cover (3014).

4. A traversing device for a flat knitting machine according to claim 1, characterized in that, The support (1) is provided with a steel wire winding disc (6), the steel wire winding disc (6) is provided with a driven gear (601), and the output end of the closed-loop motor (301) is provided with a driving gear (3012) engaged with the driven gear (601).

5. A traversing device for a flat knitting machine according to claim 4, characterized in that, Further comprising a zero position sensor (302) for detecting the initial position of threading, the zero position sensor (302) is located at the outlet of the steel wire winding disc (6).

6. A traversing device for a flat knitting machine according to claim 4, characterized in that, The support (1) is provided with a wire feeding wheel assembly (303), the wire feeding wheel assembly (303) comprises two first wire feeding wheels (3031) and two second wire feeding wheels (3032), and the steel wire (5) passes between the two first wire feeding wheels (3031) and the two second wire feeding wheels (3032).

7. A traversing device for a flat knitting machine according to claim 6, characterized in that, The two first wire feeding wheels (3031) are provided with first gears (3033), the two first gears (3033) are engaged, and one of the first gears (3033) is engaged with the driving gear (3012).

8. A traversing device for a flat knitting machine according to claim 6, characterized in that, The two second wire feeding wheels (3032) are provided with second gears (3034), the two second gears (3034) are engaged, and one of the second gears (3034) is engaged with the driving gear (3012).

9. A traversing device for a flat knitting machine according to claim 1, characterized in that, The needle plate (2) is provided with a plurality of threading needles (201) arranged along the length direction thereof, the plurality of threading needles (201) are provided with threading holes (2011), and the plurality of threading holes (2011) are coaxially arranged.

10. A traversing device for a flat knitting machine according to claim 9, characterized in that, The wire guide tube (4) is arranged in an arc shape, and the outlet end of the wire guide tube (4) is arranged opposite to the threading hole (2011).

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