Automatic wire feeding device of gas shielded welding machine

Abstract

The invention provides an automatic wire feeding device of a gas shielded welding machine, which belongs to the technical field of electric arc welding equipment and comprises a wire feeding motor, a wire feeding wheel and a wire pressing wheel. Wherein a rotating frame is installed on the side, close to the wire incoming direction, of the output end of the wire feeding motor, a movable straightening wheel and two fixed straightening wheels are installed on the two sides of the center of the interior of the rotating frame respectively, the movable straightening wheel is located between the two fixed straightening wheels, and the rotating frame is arranged to be capable of rotating around the center of the wire guiding pipe. By arranging the rotating frame, the movable straightening wheel and the fixed straightening wheel, a drawn welding wire penetrates through the space between the movable straightening wheel and the fixed straightening wheel in the rotating frame before entering the wire feeding wheel, and the movable straightening wheel and the fixed straightening wheel exert pressure on the circumference of the welding wire along with rotation of the rotating frame; the bending of the welding wire in any direction of the whole circular section can be straightened, and unsmooth wire feeding caused by the fact that the tilting distance of the welding wire is too large is avoided.

Description

Technical Field

[0001] This invention belongs to the field of welding equipment technology, specifically referring to an automatic wire feeding device for a gas shielded welding machine. Background Technology

[0002] Gas shielded welding is an arc welding device that uses gas as a protective medium. The shielding gas is continuously sprayed through the welding torch nozzle, isolating the welding arc and molten metal from the air. This effectively prevents oxygen, nitrogen, and other gases from causing defects such as oxidation and porosity in the weld, resulting in a high-quality weld joint.

[0003] The wire feeding device of a gas-shielded welding machine is the core drive system of the machine, primarily responsible for stably and uniformly feeding the welding wire from the wire spool to the contact tip of the welding torch. Its stable wire feeding performance directly determines the smoothness of the arc, the uniformity of the droplet transfer, and the final weld quality. During wire feeding, the spooled welding wire, after being released from the spool, naturally maintains a certain curvature. If the quality of the welding wire is poor, this curvature (warp) may be too large or uneven. Excessive warp will increase the resistance when the welding wire enters the wire guide tube, and may even cause jamming, thus affecting the welding quality. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the purpose of the present invention is to provide an automatic wire feeding device for a gas shielded welding machine, so as to at least partially solve the problems mentioned in the background art.

[0005] The technical solution adopted by this invention is as follows: This invention proposes an automatic wire feeding device for a gas shielded welding machine, comprising: The wire feeding motor includes two horizontally arranged output ends, and both output ends are connected to wire feeding wheels; Two pressing rollers are respectively movably positioned above the two feeding rollers; The wire feeding motor is connected to the welding machine control unit via a signal connection, so that the wire feeding motor can be automatically controlled by the welding machine control unit. The output end of the wire feeding motor is equipped with a rotating frame on the side near the wire feeding direction. The rotating frame has a movable straightening wheel and two fixed straightening wheels installed on both sides of its internal center. The movable straightening wheel is located between the two fixed straightening wheels. At the center of each end of the rotating frame, a wire guide tube is installed to guide the welding wire, allowing the welding wire to pass between the movable straightening wheel and the fixed straightening wheel. The movable straightening wheel is configured to move radially along the wire guide tube to adjust the radial pressure applied to the welding wire by the movable and fixed straightening wheels. The rotating frame is configured to rotate around the center of the wire guide tube so that the movable and fixed straightening wheels apply pressure to the welding wire for one revolution.

[0006] Furthermore, a cleaning wheel for cleaning the surface of the welding wire is installed at both ends of the interior of the rotating frame, and the cleaning surfaces of the two cleaning wheels are located on both sides of the welding wire path.

[0007] Furthermore, the cleaning wheel includes a synchronous gear and a cloth wheel that are coaxial with each other. One end of the fixed straightening wheel is provided with a transmission tooth corresponding to the synchronous gear. The transmission tooth meshes with the synchronous gear so that the fixed straightening wheel can drive the cloth wheel to rotate in the opposite direction.

[0008] Furthermore, the synchronizing gear and the cloth wheel are connected by a spring, so that the cloth wheel can move elastically along its own axis.

[0009] Furthermore, the wire feeding motor is connected to a mounting base near the side opposite to the incoming wire, and the wire guide tube is rotatably connected to the mounting base via a bearing.

[0010] Furthermore, a dust collection hood is fitted on the outer side of the rotating frame, one end of which is detachably connected to the mounting base. An air pipe is connected to one side of the mounting base and is connected to an external centrifugal fan.

[0011] Furthermore, a magnetic ring is connected to one end of the mounting base, and the dust collection cover is magnetically connected to the mounting base through the magnetic ring.

[0012] Furthermore, a straightening motor is provided on the side of the wire feeding motor near the rotating frame, and the output end of the straightening motor is connected to the wire drawing tube via a transmission belt.

[0013] Furthermore, an adjustment frame is provided on the side of the rotating frame near the movable straightening wheel. An adjustment screw is rotatably connected to the adjustment frame, and the adjustment screw is threaded to the rotating frame. Two limit rods are connected to the upper part of the adjustment frame, and the limit rods slide through the rotating frame.

[0014] Beneficial effects: 1. By setting up a rotating frame, movable straightening rollers, and fixed straightening rollers, the traction welding wire passes between the movable and fixed straightening rollers in the rotating frame before entering the wire feeding rollers. As the rotating frame rotates, the movable and fixed straightening rollers apply pressure to the welding wire around its circumference, so that any bending of the welding wire in any direction of the entire circular cross-section can be straightened, avoiding poor wire feeding caused by excessive welding wire warp.

[0015] 2. By setting up cleaning wheels, when the welding wire passes through the rotating frame, the cleaning surfaces of the cleaning wheels contact both sides of the welding wire. As the rotating frame rotates, the cleaning wheels clean the surface of the welding wire around the circumference, removing the dust adhering to the surface of the welding wire during production and reducing the probability of the welding wire getting stuck in the wire feeding hose. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an automatic wire feeding device for a gas shielded welding machine according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the rotating frame in an automatic wire feeding device for a gas shielded welding machine according to an embodiment of the present invention; Figure 3 This is a schematic diagram showing the meshing state of the transmission gear and the synchronous gear in an automatic wire feeding device for a gas shielded welding machine according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the moving direction of the welding wire in an automatic wire feeding device for a gas shielded welding machine according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the cleaning wheel in an automatic wire feeding device for a gas shielded welding machine according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the adjusting frame in an automatic wire feeding device for a gas shielded welding machine according to an embodiment of the present invention.

[0017] The components include: 1. Wire feeding motor; 11. Wire feeding wheel; 12. Wire pressing wheel; 2. Rotating frame; 21. Wire drawing tube; 3. Movable straightening wheel; 31. Adjusting frame; 32. Adjusting screw; 33. Limiting rod; 4. Fixed straightening wheel; 41. Transmission gear; 5. Mounting base; 51. Dust collection hood; 511. Magnetic ring; 52. Air pipe; 6. Straightening motor; 61. Transmission belt; 7. Cleaning wheel; 71. Synchronizing gear; 72. Cloth wheel; 73. Spring.

[0018] The accompanying drawings are provided to further understand the embodiments and form part of the specification. They are used together with the embodiments for explanation and do not constitute a limitation on the embodiments. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection.

[0020] In the description of the embodiments, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments.

[0021] Combination Figure 1 As shown, an embodiment of the present invention provides an automatic wire feeding device for a gas shielded welding machine, including a wire feeding motor 1, a wire feeding wheel 11, and a wire pressing wheel 12.

[0022] The wire feeding motor 1 includes two horizontally arranged output ends, and each output end is connected to a wire feeding wheel 11, so that the wire feeding motor 1 can drive the two wire feeding wheels 11 to rotate synchronously and in the same direction.

[0023] Two wire pressing wheels 12 are provided, and the two wire pressing wheels 12 are respectively located above the two wire feeding wheels 11. Furthermore, the wire pressing wheels 12 are movably connected to the wire feeding motor 1 through a movable frame. The wire pressing wheels 12 can swing downward and press the welding wire onto the wire feeding wheel 11 from above, and apply a certain pressure so that the wire feeding wheel 11 can pull the welding wire to move, thereby realizing wire feeding. Correspondingly, the wire pressing wheels 12 can also swing upward to facilitate the introduction of the welding wire into the wire feeding wheel 11.

[0024] It should be noted that the wire pressing wheel 12 is only connected to the housing of the wire feeding motor 1 through the movable frame and is not driven by the wire feeding motor 1. During the wire feeding process, the wire pressing wheel 12 is passively rotated by the traction of the moving welding wire.

[0025] It is understandable that the wire feeding motor 1 is connected to the welding machine control unit via a signal so that the wire feeding motor 1 can be automatically controlled by the welding machine control unit, thereby achieving automatic wire feeding.

[0026] Combination Figure 1 , Figure 2 and Figure 4 As shown, a rotating frame 2 is installed on one side of the output end of the wire feeding motor 1 in the direction of wire inlet. Movable straightening wheels 3 and two fixed straightening wheels 4 are installed on both sides of the center of the rotating frame 2. The movable straightening wheels 3 are located between the two fixed straightening wheels 4. Wire guide tubes 21 for guiding welding wire are installed at the center of both ends of the rotating frame 2.

[0027] Specifically, the welding wire is introduced into the rotating frame 2 through the wire guide tube 21 near the wire inlet end, and passes sequentially between the movable straightening wheel 3 and the fixed straightening wheel 4, and then is led out through the wire guide tube 21 at the other end. At the same time, the movable straightening wheel 3 can move radially along the wire guide tube 21. By adjusting the relative position of the movable straightening wheel 3 and the fixed straightening wheel 4, the movable straightening wheel 3 can apply radial pressure to the welding wire, uniformize the stress on the bending of the welding wire, and thus straighten the welding wire. According to the specifications of the welding wire, the magnitude of the radial pressure applied by the movable straightening wheel 3 to the welding wire is adjusted by moving the movable straightening wheel 3 to meet the straightening of welding wires of different specifications.

[0028] Furthermore, the rotating frame 2 is configured to rotate around the center of the wire guide tube 21, so that the movable straightening wheel 3 and the fixed straightening wheel 4 apply pressure to the welding wire around one circumference, straightening any bending of the welding wire in any direction across the entire circular cross-section.

[0029] Thus, the wire feeding motor 1 drives the wire feeding wheel 11 to rotate. Under the pressure of the wire pressing wheel 12, the welding wire is pulled and moved to achieve wire feeding. At the same time, before entering the wire feeding wheel 11, the pulled welding wire passes between the movable straightening wheel 3 and the fixed straightening wheel 4 in the rotating frame 2. The movable straightening wheel 3 and the fixed straightening wheel 4 apply radial pressure to the welding wire. As the rotating frame 2 rotates, the movable straightening wheel 3 and the fixed straightening wheel 4 apply pressure to the welding wire around one circumference, so that the bending of the welding wire in any direction of the entire circular cross section can be straightened, avoiding the wire feeding obstruction caused by excessive welding wire warp.

[0030] Combination Figure 2 and Figure 4 As shown, a cleaning wheel 7 for cleaning the surface of the welding wire is installed at both ends of the interior of the rotating frame 2. The cleaning surfaces of the two cleaning wheels 7 are located on both sides of the welding wire path. When the welding wire passes through the rotating frame 2, the cleaning surfaces of the two cleaning wheels 7 contact the two sides of the welding wire respectively. As the rotating frame 2 rotates, the cleaning wheels 7 clean the surface of the welding wire around the circumference, removing the dust adhering to the surface during the production of the welding wire and reducing the probability of the welding wire getting stuck in the wire feeding hose.

[0031] Combination Figure 3 and Figure 5 As shown, the cleaning wheel 7 includes a synchronous gear 71 and a cloth wheel 72 that are coaxial with each other. One end of the fixed straightening wheel 4 is provided with a transmission tooth 41 corresponding to the synchronous gear 71. The transmission tooth 41 meshes with the synchronous gear 71. When the fixed straightening wheel 4 is dragged and rotated by the welding wire, the cloth wheel 72 can also be driven to rotate under the action of the transmission tooth 41 and the synchronous gear 71, and the rotation direction is opposite. At this time, the rotation tangent direction of the area where the cloth wheel 72 contacts the welding wire is opposite to the movement direction of the welding wire (e.g., ...). Figure 4 (As shown).

[0032] Thus, the rotating frame 2 rotates to clean the surface of the welding wire by the cleaning wheel 7 around the circumference. The cleaning wheel 7 itself can rotate, applying axial friction to the welding wire, thereby improving the cleaning effect.

[0033] Combination Figure 5 As shown, the synchronous gear 71 and the cloth wheel 72 are connected by a spring 73 so that the cloth wheel 72 can move elastically along its own axis. During the process of straightening the welding wire while the rotating frame 2 rotates, the welding wire will be displaced in the radial direction. Therefore, the elastically movable cleaning wheel 7 can adapt to the displaced welding wire and always stick to the surface of the welding wire to ensure the cleaning effect.

[0034] Combination Figure 1 and Figure 2 As shown, the wire feeding motor 1 is connected to a mounting base 5 on the side near the wire feeding direction. The wire guide tube 21 is rotatably connected to the mounting base 5 through a bearing, and the mounting base 5 supports the rotating frame 2.

[0035] It should be noted that the mounting base 5 is only connected to the housing of the wire feeding motor 1, and the wire feeding motor 1 cannot drive the mounting base 5 to rotate.

[0036] Combination Figure 2 As shown, a dust collection hood 51 is fitted on the outer side of the rotating frame 2. One end of the dust collection hood 51 is detachably connected to the mounting base 5. An air pipe 52 is connected to one side of the mounting base 5. The air pipe 52 is connected to an external centrifugal fan. Under the action of the dust collection hood 51, the rotating frame 2 is semi-enclosed. The external centrifugal fan draws air from the dust collection hood 51 through the air pipe 52, so that the dust generated by the cleaning wheel 7 is removed in time and avoids re-adhering to the welding wire.

[0037] Thus, as the welding wire passes through the rotating frame 2, the cleaning surfaces of the two cleaning wheels 7 contact the two sides of the welding wire respectively. As the rotating frame 2 rotates, the cleaning wheels 7 clean the surface of the welding wire around the circumference, removing the dust adhering to the surface during the production of the welding wire. At the same time, under the action of the transmission gear 41 and the synchronous gear 71, the cloth wheel 72 can also be driven to rotate, and the rotation direction is opposite. At this time, the rotation tangent direction of the area where the cloth wheel 72 contacts the welding wire is opposite to the movement direction of the welding wire, so that the cleaning wheel 7 itself can rotate, applying axial friction force to the welding wire, thereby improving the cleaning effect.

[0038] Since the rotating frame 2 is partially enclosed by the dust collection hood 51, when cleaning the welding wire, the external centrifugal fan draws air from the dust collection hood 51 through the air pipe 52, so that the dust generated by the cleaning wheel 7 is removed in time and avoids re-adhering to the welding wire.

[0039] In a specific embodiment, a magnetic ring 511 is connected to one end of the mounting base 5. The mounting base 5 is made of a magnetically attractive material. Therefore, the dust collection cover 51 can be magnetically connected to the mounting base 5 through the magnetic ring 511, which facilitates quick disassembly and assembly when replacing the welding wire.

[0040] It should be noted that when connecting a new welding wire, the dust collection cover 51 should be removed first, and the welding wire should be passed through the dust collection cover 51. Then, the welding wire should be introduced into the rotating frame 2 and the wire feeding wheel 11 in sequence. After the welding wire is connected, the dust collection cover 51 should be installed.

[0041] Combination Figure 2 and Figure 4As shown, a straightening motor 6 is provided on the side of the wire feeding motor 1 near the rotating frame 2. A pulley is provided on the shaft of the straightening motor 6, and a pulley is also provided on the wire drawing tube 21 at the end corresponding to the straightening motor 6. The two pulleys are connected by a transmission belt 61 so that the straightening motor 6 can drive the wire drawing tube 21 and the rotating frame 2 to rotate through the transmission belt 61.

[0042] Combination Figure 6 As shown, the rotating frame 2 is provided with an adjusting frame 31 on the side near the movable straightening wheel 3. An adjusting screw 32 is rotatably connected to the adjusting frame 31, and the adjusting screw 32 is threadedly connected to the rotating frame 2. Two limiting rods 33 are connected to the upper part of the adjusting frame 31, and the limiting rods 33 slide through the rotating frame 2.

[0043] Thus, by rotating the adjusting screw 32, the adjusting frame 31 and the movable straightening wheel 3 can move under the action of the screw thread to adjust the position of the movable straightening wheel 3. At the same time, the limiting rod 33 slides synchronously along the rotating frame 2, which plays the role of limiting the adjusting frame 31 and preventing the adjusting frame 31 from rotating.

[0044] The working principle of this invention is as follows: The wire feeding motor 1 drives the wire feeding wheel 11 to rotate. Under the pressure of the wire pressing wheel 12, the welding wire is pulled and moved to achieve wire feeding. At the same time, before entering the wire feeding wheel 11, the pulled welding wire passes between the movable straightening wheel 3 and the fixed straightening wheel 4 in the rotating frame 2. The movable straightening wheel 3 and the fixed straightening wheel 4 apply radial pressure to the welding wire. While the wire is being fed, the straightening motor 6 drives the rotating frame 2 to rotate. As the rotating frame 2 rotates, the movable straightening wheel 3 and the fixed straightening wheel 4 apply pressure to the welding wire around its circumference, so that the bending of the welding wire in any direction of the entire circular cross section can be straightened, avoiding the wire feeding difficulties caused by excessive welding wire warp.

[0045] As the welding wire passes through the rotating frame 2, the cleaning surfaces of the two cleaning wheels 7 contact the two sides of the welding wire respectively. As the rotating frame 2 rotates, the cleaning wheels 7 clean the surface of the welding wire around the circumference, removing the dust adhering to the surface during the production of the welding wire and reducing the probability of the welding wire getting stuck in the wire feeding hose.

[0046] When the fixed straightening wheel 4 is dragged and rotated by the welding wire, the cloth wheel 72 can also be driven to rotate under the action of the transmission gear 41 and the synchronous gear 71, and the rotation direction is opposite. At this time, the rotation tangent direction of the area where the cloth wheel 72 contacts the welding wire is opposite to the movement direction of the welding wire, so that the cleaning wheel 7 itself can rotate, apply axial friction force to the welding wire, and improve the cleaning effect.

[0047] Since the rotating frame 2 is partially enclosed by the dust collection hood 51, when cleaning the welding wire, the external centrifugal fan draws air from the dust collection hood 51 through the air pipe 52, so that the dust generated by the cleaning wheel 7 is removed in time and avoids re-adhering to the welding wire.

[0048] In summary, by setting up a rotating frame 2, a movable straightening wheel 3, and a fixed straightening wheel 4, the traction welding wire passes between the movable straightening wheel 3 and the fixed straightening wheel 4 inside the rotating frame 2 before entering the wire feeding wheel 11. As the rotating frame 2 rotates, the movable straightening wheel 3 and the fixed straightening wheel 4 apply pressure to the welding wire around its circumference, so that any bending of the welding wire in any direction of the entire circular cross-section can be straightened, avoiding poor wire feeding caused by excessive welding wire warp.

[0049] By setting up the cleaning wheel 7, when the welding wire passes through the rotating frame 2, the cleaning surface of the cleaning wheel 7 contacts both sides of the welding wire. As the rotating frame 2 rotates, the cleaning wheel 7 cleans the surface of the welding wire around the circumference, removing the dust adhering to the surface during the production of the welding wire and reducing the probability of the welding wire getting stuck in the wire feeding hose.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0051] The embodiments have been described above, and such description is not restrictive. The figures shown are only one embodiment, and the actual structure is not limited to this. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the inventive spirit, such design should fall within the scope of protection.

Claims

1. An automatic wire feeding device for a gas shielded welding machine, characterized in that, include: The wire feeding motor (1) includes two horizontally arranged output ends, and both output ends are connected to wire feeding wheels (11). Two pressing rollers (12) are respectively movably disposed above the two feeding rollers (11); The wire feeding motor (1) is signal-connected to the welding machine control unit so that the wire feeding motor (1) can be automatically controlled by the welding machine control unit; Among them, a rotating frame (2) is installed on the side of the output end of the wire feeding motor (1) near the direction of the incoming wire. A movable straightening wheel (3) and two fixed straightening wheels (4) are respectively installed on both sides of the inner center of the rotating frame (2). The movable straightening wheel (3) is located between the two fixed straightening wheels (4). The rotating frame (2) has wire guide tubes (21) installed at the center of both ends for guiding the welding wire. The movable straightening wheel (3) is configured to move radially along the wire guide tube (21), and the rotating frame (2) is configured to rotate around the center of the wire guide tube (21) so that the movable straightening wheel (3) and the fixed straightening wheel (4) apply pressure to the welding wire for one revolution.

2. The automatic wire feeding device for gas shielded welding machine according to claim 1, characterized in that: The rotating frame (2) has a cleaning wheel (7) installed at both ends inside for cleaning the surface of the welding wire, and the cleaning surfaces of the two cleaning wheels (7) are located on both sides of the welding wire path.

3. The automatic wire feeding device for gas shielded welding machine according to claim 2, characterized in that: The cleaning wheel (7) includes a synchronous gear (71) and a cloth wheel (72) that are coaxial with each other. One end of the fixed straightening wheel (4) is provided with a transmission tooth (41) corresponding to the synchronous gear (71). The transmission tooth (41) meshes with the synchronous gear (71) so that the fixed straightening wheel (4) can drive the cloth wheel (72) to rotate in the opposite direction.

4. The automatic wire feeding device for a gas shielded welding machine according to claim 3, characterized in that: The synchronous gear (71) and the cloth wheel (72) are connected by a spring (73) so that the cloth wheel (72) can move elastically along its own axis.

5. The automatic wire feeding device for a gas shielded welding machine according to claim 1, characterized in that: The wire feeding motor (1) is connected to a mounting base (5) on the side opposite to the incoming wire, and the wire guide tube (21) is rotatably connected to the mounting base (5) via a bearing.

6. The automatic wire feeding device for a gas shielded welding machine according to claim 5, characterized in that: The rotating frame (2) is fitted with a dust collection hood (51) on its outer side. One end of the dust collection hood (51) is detachably connected to the mounting base (5). One side of the mounting base (5) is connected to an air pipe (52), which is connected to an external centrifugal fan.

7. The automatic wire feeding device for a gas shielded welding machine according to claim 6, characterized in that: One end of the mounting base (5) is connected to a magnetic ring (511), and the dust collection cover (51) is magnetically connected to the mounting base (5) through the magnetic ring (511).

8. The automatic wire feeding device for a gas shielded welding machine according to claim 1, characterized in that: The wire feeding motor (1) is provided with a straightening motor (6) on the side near the rotating frame (2), and the output end of the straightening motor (6) is connected to the wire drawing tube (21) through a transmission belt (61).

9. The automatic wire feeding device for a gas shielded welding machine according to claim 1, characterized in that: The rotating frame (2) has an adjustment frame (31) on the side near the movable straightening wheel (3). An adjustment screw (32) is rotatably connected to the adjustment frame (31), and the adjustment screw (32) is threaded to the rotating frame (2). Two limit rods (33) are connected to the upper part of the adjustment frame (31), and the limit rods (33) slide through the rotating frame (2).

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