A laser engraving machine optical path focusing device

Abstract

This invention relates to the field of laser engraving technology and discloses an optical path focusing device for a laser engraving machine. The device includes an optical fiber line, below which are connected a QBH assembly, a protective lens assembly, a collimating lens assembly, and a rotating mechanism. Below the rotating mechanism is an adjustment mechanism, which includes a vertical angle adjustment device for adjusting the angle of the engraving head; a flat light refraction device for reflecting the light path during angle adjustment; and a focusing lens replacement device for quick replacement of the focusing lens. This optical path focusing device for a laser engraving machine, through the adjustment mechanism, allows for lateral angle adjustment via a first and second rotating node, enabling the laser engraving head to engrave different angles on the object below. The modular mirror design simplifies the disassembly process by allowing the lens to be removed by opening the sealed cover, reducing operational difficulty.

Description

Technical Field

[0001] This invention relates to the field of laser engraving technology, specifically to an optical path focusing device for a laser engraving machine. Background Technology

[0002] Laser engraving machines use high-energy-density laser beams to induce physical or chemical changes in workpieces to achieve engraving. Their operation involves laser technology, which provides the energy required for engraving; optical path system technology, used to transmit and focus the laser; control system technology, which precisely controls the laser engraving path and parameters; and machining technology, ensuring the relative motion accuracy between the workpiece and the laser beam. These technologies work together to give laser engraving advantages such as high precision and high speed, making it widely used in industries such as electronics and automobiles.

[0003] Chinese Patent CN119609422B, published on April 18, 2025, discloses a laser engraving device and a beam quality detection method. Through a laser timing and positioning calibration mechanism, it provides timely self-inspection and calibration data, allowing maintenance personnel to quickly determine the cause of faults based on the laser beam fault calibration data. This significantly improves the efficiency of post-processing maintenance of the laser engraving device and greatly shortens the duration of processing faults. It solves the problem of the inability to quickly repair laser engraving devices, leading to a significant decrease in post-processing maintenance efficiency and a significant increase in the duration of processing faults. However, when inspecting lenses, this laser engraving device requires the entire device to be gradually disassembled from bottom to top, a time-consuming and labor-intensive process. Furthermore, when engraving and cutting objects, the surface of the object is not necessarily flat, making it impossible to ensure that the laser is perpendicular to the object. This causes the laser beam focal point to shift due to changes in the incident angle, resulting in a deviation between the actual working area and the preset path, leading to problems such as skewed lines and dimensional errors. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an optical path focusing device for a laser engraving machine, which solves the problems of time-consuming and labor-intensive removal processes and laser beam focus point shift caused by the inability to ensure laser perpendicularity when engraving and cutting objects.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A focusing device for a laser engraving machine includes an optical fiber cable. A QBH (Quality By-Help) assembly is connected below the optical fiber cable. An upper protective lens assembly is connected below the QBH assembly. A collimating lens assembly is connected below the upper protective lens assembly. A rotating mechanism is located below the collimating lens assembly. A fixing block is located on one side of the rotating mechanism. An adjusting mechanism is located below the rotating mechanism. A lower protective lens assembly is located below the adjusting mechanism. A TRA (Traction Control Array) assembly is connected below the lower protective lens assembly. A TRA connector is connected below the TRA assembly. A nozzle assembly is connected below the TRA connector. The adjusting mechanism includes a focusing lens replacement device for quick replacement of the focusing lens; a flat light refraction device for reflecting the light path during angle adjustment; and an angle vertical adjustment device for adjusting the angle of the engraving machine head.

[0007] Preferably, the flat light refraction device includes a first rotating node, a parallel light refraction pipe fixedly connected to one side surface of the first rotating node, a second rotating node fixedly connected to one side surface of the parallel light refraction pipe, a locking tooth fixedly connected to the outer side surface of the first rotating node, a fixing tooth engaging the outer side of the locking tooth, and a stable connecting frame fixedly connected to one side surface of the fixing tooth and one side surface of the angle adjustment motor.

[0008] Preferably, one set of the angle adjustment motors is provided on the outer surface of the first rotation node and the second rotation node, and the interior of the stable connecting frame is composed of multiple equilateral triangular plates spliced ​​together.

[0009] Preferably, the flat light refraction device includes a fixed folding arm, one end of which is rotatably connected to a main rotating shaft, and the main rotating shaft is rotatably connected to a movable folding arm. A secondary rotating shaft is rotatably connected to one side surface of the fixed folding arm and the movable folding arm, and a rotating arm is rotatably connected to one side surface of the secondary rotating shaft. A limiting groove rod is slidably connected to one side surface of the rotating arm, and a movable rod is slidably connected to the inner side of the limiting groove rod. A fixed connecting plate is fixedly connected to one end of the movable rod, and a refractor is fixedly connected to one side surface of the fixed connecting plate.

[0010] Preferably, a set of secondary rotating shafts is provided on the upper surface of both the fixed and movable folding arms, and the distance from the main rotating shaft is the same. The fixed connecting plate and the movable rod are perpendicularly connected to each other.

[0011] Preferably, the focusing lens replacement device includes a focusing tube, a dustproof window on one side surface of the focusing tube, an inspection window on the other side surface of the focusing tube, a movable tube slidably connected to the inner surface of the focusing tube, a focusing lens engaged with the inner surface of the movable tube, a return spring fixedly connected to one side surface of the focusing lens, a locking block fixedly connected to one side surface of the return spring, an adjusting rack fixedly connected to the outer surface of the movable tube, an adjusting gear meshing with one side surface of the adjusting rack, and an adjusting port fixedly connected to one side surface of the adjusting gear.

[0012] Preferably, each of the dustproof windows is equipped with a sealing cover, and a set of reset springs and locking blocks are symmetrically arranged on both sides of the focusing lens, and the focusing lens is fixedly connected to the movable tube through the reset springs and locking blocks.

[0013] Preferably, the rotating mechanism includes an upper fixed plate, a ball bearing is rotatably connected to the lower surface of the upper fixed plate, a lower fixed plate is slidably connected to the lower surface of the ball bearing, a limit ring is slidably connected to the outer surface of the lower fixed plate, a driven gear is fixedly connected to the outer surface of the lower fixed plate, a driving gear is meshed with one side surface of the driven gear, and a rotating motor is fixedly connected to the upper surface of the driving gear.

[0014] Preferably, sixteen sets of fixed plates above the ball bearing are symmetrically arranged along the central axis, and the upper fixed plate is fitted to the lower fixed plate through a limiting ring.

[0015] Compared with the prior art, the present invention provides an optical path focusing device for a laser engraving machine, which has the following beneficial effects:

[0016] 1. The optical path focusing device of this laser engraving machine, through the setting of the adjustment mechanism, drives the lower fixed plate and the entire assembly below to rotate vertically along the central axis of the upper fixed plate during use. The first rotation node and the second rotation node adjust the lateral angle of the device, enabling the laser engraving head to engrave different angles of the object to be engraved below. It can flexibly adapt to different angles of the object, ensure that the laser is incident vertically, eliminate the need for frequent workpiece movement, and improve engraving accuracy and efficiency.

[0017] 2. The optical path focusing device of this laser engraving machine, through the modular mirror design, allows for easy disassembly by opening the dustproof windows of the upper protective mirror assembly, collimating mirror assembly, focusing mirror, and the sealed cover of the lower protective mirror assembly, and then removing and replacing the individual lenses. Compared to the existing method of disassembling the laser engraving head step by step from bottom to top, this method eliminates the need to disassemble the entire laser engraving head. Lenses can be directly replaced by opening the sealed structures of each component, simplifying the disassembly process, significantly reducing maintenance time, and lowering operational difficulty. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the optical path focusing device for a laser engraving machine proposed in this invention;

[0019] Figure 2 This is a schematic diagram showing the interaction between the protective lens assembly, the collimating lens assembly, and the rotating mechanism of the present invention;

[0020] Figure 3 This is a schematic cross-sectional view of the optical path focusing device of the laser engraving machine of the present invention;

[0021] Figure 4 This is a schematic diagram of the flat light refraction device proposed in this invention;

[0022] Figure 5 This is a schematic diagram showing the stable connection relationship between the vertical angle adjustment device of the present invention and the frame.

[0023] Figure 6 This is a schematic diagram of the rotating mechanism of the present invention;

[0024] Figure 7 This is a schematic diagram of the focusing lens replacement device proposed in this invention;

[0025] Figure 8 This is a schematic diagram showing the interaction between the movable tube and the focusing tube in the focusing lens replacement device of the present invention;

[0026] Figure 9 This is a schematic diagram showing the interaction between the focusing lens, the reset spring, and the locking block of the present invention.

[0027] In the diagram: 1. Fiber optic cable; 2. QBH assembly; 3. Upper protective lens assembly; 4. Collimating lens assembly; 5. Rotation mechanism; 501. Upper fixed plate; 502. Ball bearing; 503. Lower fixed plate; 504. Limiting ring; 505. Driven gear; 506. Driving gear; 507. Rotation motor; 6. Fixed block; 7. Adjustment mechanism; 701. First rotation node; 702. Parallel light refraction channel; 703. Second rotation node; 704. Engaging gear; 705. Fixed gear; 706. Angle adjustment motor; 707. Stable connecting frame; 708. Fixed... 709. Folding arm; 710. Main rotating shaft; 711. Movable folding arm; 712. Secondary rotating shaft; 713. Rotating arm; 714. Limiting groove rod; 715. Movable rod; 716. Fixed connecting plate; 717. Refracting mirror; 718. Focusing tube; 719. Dustproof window; 720. Inspection window; 721. Movable tube; 722. Focusing lens; 723. Return spring; 724. Locking block; 725. Adjusting rack; 726. Adjusting gear; 727. Adjusting port; 8. Lower protective lens assembly; 9. TRA assembly; 10. TRA connection port; 11. Nozzle assembly. Detailed Implementation

[0028] The technical solutions of 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 of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1-9 A focusing device for a laser engraving machine includes an optical fiber cable 1, a QBH assembly 2 connected below the optical fiber cable 1, an upper protective lens assembly 3 connected below the QBH assembly 2, a collimating lens assembly 4 connected below the upper protective lens assembly 3, a rotating mechanism 5 disposed below the collimating lens assembly 4, a fixing block 6 disposed on one side of the rotating mechanism 5, an adjusting mechanism 7 disposed below the rotating mechanism 5, a lower protective lens assembly 8 disposed below the adjusting mechanism 7, a TRA assembly 9 connected below the lower protective lens assembly 8, and a TRA connector 10 connected below the TRA assembly 9. Below the interface 10 is a nozzle assembly 11, in which the QBH assembly 2 is a beam transmission connector, short for "QuartzBlockHeader", which provides beam positioning, alignment and protection functions to ensure that the laser output can be effectively transmitted and used. It plays a key role in guiding the laser beam in the optical path focusing device of this laser engraving machine. The TRA connector 10, short for "TransmissionAdapter", is used for real-time capture and analysis of the core characteristics of the laser to ensure the stability of the laser transmission path.

[0030] The adjustment mechanism 7 includes an angle vertical adjustment device for adjusting the angle of the engraving machine head. The angle vertical adjustment device includes a first rotating node 701. A parallel light refraction pipe 702 is fixedly connected to one side surface of the first rotating node 701. A second rotating node 703 is fixedly connected to one side surface of the parallel light refraction pipe 702. A locking tooth 704 is fixedly connected to the outer surface of the first rotating node 701. A fixing tooth 705 engages with the outer side of the locking tooth 704. An angle adjustment motor 706 is fixedly connected to one side surface of the fixing tooth 705, and a stable connecting frame 707 is fixedly connected to one side surface of the fixing tooth 705. When the angle needs to be adjusted, the angle adjustment motor 706 drives the first rotating node 701 and the second rotating node 703 to rotate and adjust. The locking tooth 704 and the fixing tooth 705 are provided on the outer surfaces of the first rotating node 701 and the second rotating node 703. The arrangement of the two allows the device to maintain a fixed angle after the motor stops running. The locking tooth 704 and the fixing tooth 705 adopt a mechanical meshing method to ensure that the position remains accurate after the angle is adjusted.

[0031] Angle adjustment motor 706 is provided on the outer surface of the first rotation node 701 and the second rotation node 703. The interior of the stable connecting frame 707 is composed of multiple equilateral triangular plates. In use, the arrangement of multiple equilateral triangles inside the stable connecting frame 707 can evenly distribute external forces to the entire frame, effectively resisting the vibration, torque and gravity load generated when the adjustment mechanism is working, and avoiding frame deformation from affecting the optical path accuracy.

[0032] The adjustment mechanism 7 includes a flat light refraction device for reflecting light during angle adjustment. The flat light refraction device includes a fixed folding arm 708, one end of which is rotatably connected to a main rotating shaft 709. A movable folding arm 710 is rotatably connected to the main rotating shaft 709. A secondary rotating shaft 711 is rotatably connected to one side surface of the fixed folding arm 708 and the movable folding arm 710. A rotating arm 712 is rotatably connected to one side surface of the secondary rotating shaft 711. A limiting groove rod 713 is slidably connected to one side surface of the rotating arm 712. A movable rod 714 is slidably connected to the inner side of the limiting groove rod 713. A fixed connecting plate 715 is fixedly connected to one end of the movable rod 714. A refractor 7 is fixedly connected to one side surface of the fixed connecting plate 715. 16. In use, the first rotating node 701 bends with the parallel light refraction channel 702, causing the movable folding arm 710 to approach the fixed folding arm 708 via the main rotating shaft 709. At this time, the rotating arm 712 on the secondary rotating shaft 711 rotates, pushing the movable rod 714 in the limiting groove rod 713. Even if the fixed connecting plate 715 is pushed upward, the angle of the refracting mirror 716 changes. During this process, the angle between the movable folding arm 710 and the limiting groove rod 713 is the same as that between the fixed folding arm 708 and the limiting groove rod 713. Since the fixed connecting plate 715 and the limiting groove rod 713 are perpendicular to each other, the normal of the reflected light can be made collinear with the limiting groove rod 713, and the light is parallel to the parallel light refraction channel 702 after reflection.

[0033] A set of secondary rotating shafts 711 are provided on the upper surface of both the fixed hinge arm 708 and the movable hinge arm 710, and are equidistant from the main rotating shaft 709. The fixed connecting plate 715 and the movable rod 714 are perpendicularly connected. The secondary rotating shafts 711 are symmetrically distributed on the fixed hinge arm 708 and the movable hinge arm 710, and are equidistant from the main rotating shaft 709, forming a parallelogram linkage mechanism. When the movable hinge arm 710 rotates around the main rotating shaft 709, the two secondary rotating shafts move synchronously, ensuring that the refractor maintains a symmetrical relationship with the incident light during angle adjustment. The fixed connecting plate 715 is perpendicularly connected to the movable rod 714. Combined with the motion characteristics of the parallelogram mechanism, this ensures that the normal direction of the refractor is always collinear with the axis of the limiting groove rod 713. During angle adjustment, regardless of how the movable hinge arm swings, the refractor 716 will automatically adjust to the optimal reflection angle, ensuring that the reflected light is strictly parallel to the parallel light refraction channel 702.

[0034] The adjustment mechanism 7 includes a focusing lens replacement device for quick replacement of the focusing lens. The focusing lens replacement device includes a focusing tube 717. A dustproof window 718 is provided on one side surface of the focusing tube 717, and an inspection window 719 is provided on the other side surface of the focusing tube 717. A movable tube 720 is slidably connected to the inner surface of the focusing tube 717. A focusing lens 721 is engaged with the inner surface of the movable tube 720. A return spring 722 is fixedly connected to one side surface of the focusing lens 721, and a locking block 723 is fixedly connected to one side surface of the return spring 722. An adjusting rack 724 is fixedly connected to the outer surface of the movable tube 720. An adjusting gear 725 meshes with one side surface of the adjusting rack 724, and an adjusting port 726 is fixedly connected to one side surface of the adjusting gear 725. When the focusing lens needs to be replaced, the dustproof window 718 is opened, and the lens is quickly replaced. The focusing lens 721 is then removed using the handle of the focusing lens 721, and a new focusing lens 721 is inserted. Due to the setting of the return spring 722 and the locking block 723, the new focusing lens 721 will be inserted into the corresponding slot in the movable tube 720. Then, the dustproof window 718 is closed to replace the focusing lens. An adjustment port 726 is provided on the outside of the focusing tube 717. If the focusing lens needs to be adjusted, simply turn the adjustment port 726. The adjustment port 726 drives the adjustment rack 724 to move through the adjustment gear 725. Since the adjustment rack 724 is fixedly connected to the movable tube 720, the movable tube 720 will slide up and down along the inner wall of the focusing tube 717, directly exposing the focusing lens through the dustproof window 718. The lens can be removed and installed by hand without disassembling other components or using additional tools. Compared to the maintenance method of traditional laser engraving machines that require disassembling the optical path system layer by layer, this method significantly shortens the replacement time. Furthermore, the rotation operation of the adjustment port, combined with the inspection window, allows for real-time observation of lens position changes, further improving adjustment accuracy.

[0035] Each dustproof window 718 is equipped with a sealing cover. A set of return springs 722 and locking blocks 723 are symmetrically arranged on both sides of the focusing lens 721. The focusing lens 721 is fixedly connected to the movable tube 720 through the return springs 722 and locking blocks 723. Dust, smoke and other contaminants generated during laser engraving can easily adhere to the surface of the focusing lens, reducing light transmittance and affecting laser energy density. The sealing cover can completely seal the dustproof window in the non-maintenance state, forming a physical barrier to effectively prevent external contaminants from entering the optical path system, extending the lens cleaning cycle and service life. The spring locking design allows the lens replacement operation to be completed by overcoming the spring force, without the need for complicated tools. At the same time, the elastic memory characteristics of the spring ensure that the installation position of the lens is consistent after each replacement, avoiding the tedious process of recalibrating the optical path.

[0036] The rotating mechanism 5 includes an upper fixed disk 501, with a ball bearing 502 rollingly connected to the lower surface of the upper fixed disk 501. A lower fixed disk 503 is slidably connected to the lower surface of the ball bearing 502. A limit ring 504 is slidably connected to the outer surface of the lower fixed disk 503. A driven gear 505 is fixedly connected to the outer surface of the lower fixed disk 503. A driving gear 506 meshes with one side surface of the driven gear 505. A rotating motor 507 is fixedly connected to the upper surface of the driving gear 506. In use, the rotating motor 507 starts and drives the driving gear 506 to rotate. Since the driving gear 506 and the driven gear 505 mesh with each other, the driven gear 505 will drive the lower fixed disk 503 to rotate, so that the entire device below can rotate.

[0037] Sixteen sets of balls are symmetrically arranged along the central axis of the upper fixed plate 501 above the ball bearing 502. The upper fixed plate 501 is in contact with the lower fixed plate 503 through the limiting ring 504. During use, the symmetrical distribution of the central axis of the sixteen sets of balls above the ball bearing 501 can evenly distribute the pressure or load between the upper and lower fixed plates to each ball bearing, avoiding wear or deformation caused by excessive local force. Moreover, the symmetrically distributed multiple sets of balls can form uniform support points, reducing shaking or jamming during the relative movement of the upper and lower fixed plates, and ensuring the smoothness of the movement process. At the same time, the rolling friction characteristics of the balls themselves are smaller than the sliding friction resistance. Combined with the multiple symmetrical sets, energy loss can be further reduced and movement efficiency can be improved. The limiting ring 504 can provide a clear constraint on the relative position of the upper fixed plate 501 and the lower fixed plate 503, ensuring that the two always maintain the coaxial or preset relative position relationship during assembly or movement, avoiding structural interference caused by misalignment.

[0038] Working principle: This laser engraving machine's optical path focusing device, when angle adjustment is required, drives the first rotating node 701 and the second rotating node 703 to rotate for adjustment via an angle adjustment motor 706. Engaging teeth 704 and fixing teeth 705 are provided on the outer surfaces of the first rotating node 701 and the second rotating node 703. Their arrangement ensures the device maintains a fixed angle after the motor stops. The engaging teeth 704 and fixing teeth 705 employ a mechanical meshing method to ensure precise positioning after angle adjustment. The internal planar refraction device rotates simultaneously with the outer mechanism, while the movable folding arm 710 moves closer to the fixed folding arm 708 via the main rotating shaft 709. At this time, the rotating arm 712 on the secondary rotating shaft 711 rotates, pushing the movable rod 714 in the limiting groove rod 713. This causes the fixed connecting plate 715 to push upward, changing the angle of the refraction mirror 716. During this process, the angle between the movable folding arm 710 and the limiting groove rod 713 is the same as that between the fixed folding arm 708 and the limiting groove rod 713. Furthermore, the fixed connecting plate 715 and the limiting groove rod 713 are perpendicular to each other. This ensures that the normal of the reflected light is collinear with the limiting groove 713, and the light is parallel to the parallel light refraction pipe 702 after reflection. To quickly remove the focusing lens 721, simply open the dustproof window 718, then remove the focusing lens 721 using its handle. Insert the new focusing lens 721; due to the reset spring 722 and the locking block 723, the new focusing lens 721 will lock into the corresponding slot in the movable tube 720. Then close the dustproof window 718 to complete the process. The focusing lens replacement process utilizes an adjustment port 726 located on the outer side of the focusing tube 717. To adjust the focusing lens, simply rotate the adjustment port 726. The adjustment port 726, via the adjustment gear 725, drives the adjustment rack 724. Since the adjustment rack 724 is fixedly connected to the movable tube 720, the movable tube 720 slides up and down along the inner wall of the focusing tube 717, directly exposing the focusing lens through the dustproof window 718. The lens can be removed and installed manually without disassembling other components or using additional tools. Compared to the maintenance method of traditional laser engraving machines that requires disassembling the optical path system layer by layer, this significantly shortens replacement time. Furthermore, the rotation operation of the adjustment port, combined with the inspection window, allows real-time observation of lens position changes, further improving adjustment accuracy.

[0039] 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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A laser engraving machine's optical path focusing device, comprising an optical fiber (1), characterized in that: A QBH assembly (2) is connected below the fiber optic cable (1). An upper protective lens assembly (3) is connected below the QBH assembly (2). A collimating lens assembly (4) is connected below the upper protective lens assembly (3). A rotating mechanism (5) is provided below the collimating lens assembly (4). A fixing block (6) is provided on one side of the rotating mechanism (5). An adjusting mechanism (7) is provided below the rotating mechanism (5). A lower protective lens assembly (8) is provided below the adjusting mechanism (7). A TRA assembly (9) is connected below the lower protective lens assembly (8). A TRA connector (10) is connected below the TRA assembly (9). A nozzle assembly (11) is connected below the TRA connector (10). The adjustment mechanism (7) includes an angle vertical adjustment device for adjusting the angle of the engraving head. The angle vertical adjustment device includes a first rotating node (701). A parallel light refraction pipe (702) is fixedly connected to one side surface of the first rotating node (701). A second rotating node (703) is fixedly connected to one side surface of the parallel light refraction pipe (702). A locking tooth (704) is fixedly connected to the outer surface of the first rotating node (701). A fixing tooth (705) meshes with the outer side of the locking tooth (704). A stable connecting frame (707) is fixedly connected to one side surface of the angle adjustment motor (706). A set of angle adjustment motors (706) is provided on the outer surfaces of the first rotating node (701) and the second rotating node (703). The interior of the stable connecting frame (707) is composed of multiple equilateral triangular plates spliced ​​together. The adjustment mechanism (7) further includes a flat light refraction device for reflecting the light path during angle adjustment. The flat light refraction device includes a fixed folding arm (708), one end of which is rotatably connected to a main rotating shaft (709). The main rotating shaft (709) is rotatably connected to a movable folding arm (710). A secondary rotating shaft (711) is rotatably connected to one side surface of the fixed folding arm (708) and the movable folding arm (710). A rotating arm (712) is rotatably connected to one side surface of the secondary rotating shaft (711). One side surface of the rotating arm (712) is connected to a rotating arm (712). A limiting groove rod (713) is slidably connected to the side surface. A movable rod (714) is slidably connected to the inner side of the limiting groove rod (713). A fixed connecting plate (715) is fixedly connected to one end of the movable rod (714). A refractor (716) is fixedly connected to one side surface of the fixed connecting plate (715). A set of secondary rotating shafts (711) are provided on the upper surfaces of the fixed folding arm (708) and the movable folding arm (710), and the distance from them is the same as that from the main rotating shaft (709). The fixed connecting plate (715) and the movable rod (714) are perpendicularly connected to each other. The adjustment mechanism (7) also includes a focusing lens replacement device for quick replacement of the focusing lens.

2. The optical path focusing device for a laser engraving machine according to claim 1, characterized in that: The focusing lens replacement device includes a focusing tube (717), a dustproof window (718) on one side surface of the focusing tube (717), an inspection window (719) on the other side surface of the focusing tube (717), a movable tube (720) slidably connected to the inner surface of the focusing tube (717), a focusing lens (721) engaging with the inner surface of the movable tube (720), a return spring (722) fixedly connected to one side surface of the focusing lens (721), a locking block (723) fixedly connected to one side surface of the return spring (722), an adjusting rack (724) fixedly connected to the outer surface of the movable tube (720), an adjusting gear (725) meshing with one side surface of the adjusting rack (724), and an adjusting port (726) fixedly connected to one side surface of the adjusting gear (725).

3. The optical path focusing device for a laser engraving machine according to claim 2, characterized in that: The dustproof window (718) is provided with a closed cover. The reset spring (722) and the locking block (723) are symmetrically arranged on both sides of the focusing lens (721), and the focusing lens (721) is fixedly connected to the movable tube (720) through the reset spring (722) and the locking block (723).

4. The optical path focusing device for a laser engraving machine according to claim 1, characterized in that: The rotating mechanism (5) includes an upper fixed plate (501), a ball bearing (502) is rolledly connected to the lower surface of the upper fixed plate (501), a lower fixed plate (503) is slidably connected to the lower surface of the ball bearing (502), a limit ring (504) is slidably connected to the outer surface of the lower fixed plate (503), a driven gear (505) is fixedly connected to the outer surface of the lower fixed plate (503), a driving gear (506) is meshed on one side surface of the driven gear (505), and a rotating motor (507) is fixedly connected to the upper surface of the driving gear (506).

5. The optical path focusing device for a laser engraving machine according to claim 4, characterized in that: The upper fixed plate (501) of the ball bearing (502) is symmetrically arranged with sixteen sets of fixed plates on the central axis. The upper fixed plate (501) is in contact with the lower fixed plate (503) through the limiting ring (504).

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