Finishing method and finishing device for intaglio printing roller for anti-counterfeit printing

Abstract

The invention relates to a finishing method and a finishing device for an intaglio printing roller for anti-counterfeit printing. The trimming method comprises the following steps that (1) wax filler is arranged on one side or two sides of the ink cell position needing anti-counterfeiting, the wax filler is used for blocking the ink cell on the corresponding side, and the ink cell section on one side of the wax filler or the ink cell section between two pieces of wax filler forms a trimming section; and (2) spraying an anti-corrosion wax layer into the finishing section in the step (1). And (3) a wax suction pipe with a heating wire at the end extends into the finishing section in the step (2), the heating wire melts the wax layer on the bottom wall of the finishing section, and the melted wax liquid is sucked away through the wax suction pipe. And (4) corrosive liquid is injected into the finishing section in the step (3) so as to corrode the bottom wall of the finishing section. And (5) after corrosion is conducted for a set time, hot water with the temperature being 50 DEG C or above is adopted for flushing the intaglio printing roller so as to clean wax filler and a wax layer on the intaglio printing roller. Ink cells of patterns on the printing roller can be trimmed, and a better anti-fake effect is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of gravure printing, and in particular to a trimming method and a trimming device for a gravure printing roller used for anti-counterfeiting printing. Background Art

[0002] Gravure printing, a printing method, holds a crucial position in the fields of printing, packaging, and graphic publishing, owing to its advantages, such as a thick ink layer, vibrant colors, high saturation, long-lasting printing plates, stable print quality, and fast printing speeds. Gravure printing involves coating the entire surface of the plate roller with ink. A specialized scraper removes the ink from the blank areas, leaving only the ink in the cells of the graphic area. Then, under high pressure, the ink is transferred to the substrate surface, resulting in a printed product.

[0003] However, gravure printing also presents a problem: the pattern is difficult to modify after platemaking, requiring a new platemaking process. This creates a potential security risk during anti-counterfeiting. This type of anti-counterfeiting can be easily detected and circumvented, leading to the appearance of counterfeit products. Furthermore, there is also the risk of information leaks from third parties involved in platemaking. Therefore, to enhance anti-counterfeiting effectiveness, manufacturers must trim finished gravure printing rollers to ensure that the printed pattern is distinct from the original platemaking pattern. Summary of the Invention

[0004] The object of the present invention is to provide a trimming method for a gravure printing roller used for anti-counterfeiting printing, so as to improve the anti-counterfeiting effect; at the same time, the object of the present invention is also to provide a trimming device using the above-mentioned trimming method.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical solution for a method for trimming a gravure printing roller for anti-counterfeiting printing: a method for trimming a gravure printing roller for anti-counterfeiting printing, comprising the following steps:

[0006] 1) Wax fillers are placed on one or both sides of the cell locations where anti-counterfeiting is required. The wax fillers are used to block the cells on the corresponding side, so that the cell segment on one side of the wax filler or the cell segment between two wax fillers forms a trimming segment;

[0007] 2) spraying an anti-corrosion wax layer into the trimming section of step 1);

[0008] 3) inserting a wax suction pipe with a heating wire at the end into the trimming section in step 2), the heating wire melts the wax layer on the bottom wall of the trimming section and the wax suction pipe sucks away the melted wax liquid;

[0009] 4) injecting a corrosive liquid into the trimming section in step 3) to corrode the bottom wall of the trimming section;

[0010] 5) After the set etching time, the gravure printing roller is rinsed with hot water above 50°C to clean the wax filling and wax layer thereon.

[0011] In step 5), after a certain period of corrosion, the corrosion liquid is extracted and new corrosion liquid is re-injected, and this process is repeated two or more times until the desired corrosion effect is achieved.

[0012] A dressing device for realizing the above-mentioned dressing method of the present invention adopts the following technical solution: a dressing device capable of realizing the above-mentioned dressing method comprises a device frame for rotatably mounting the printing roller to be dressed, the device frame having a crossbeam located above the printing roller, the length direction of the crossbeam being parallel to the axis direction of the printing roller, and two or more dressing mechanisms being movably provided on the crossbeam; each dressing mechanism comprises a hanging frame movably mounted on the crossbeam, an electric telescopic rod being provided on the hanging frame, a horizontal mounting plate being rotatably provided on the movable end of the electric telescopic rod, a first gear being provided on the movable end, a second gear being transmitted to the first gear and a gear driving the second gear to rotate a first driving motor; a horizontal mounting rod is rotatably provided on the horizontal mounting plate, and a second driving motor that drives the horizontal mounting rod to rotate is provided on the horizontal mounting plate, and two wax injection pipes are horizontally arranged on the horizontal mounting rod, which are used to inject wax filler on one side or both sides of the mesh cell position where anti-counterfeiting is required, so that the mesh cell segment on one side of the wax filler or the mesh cell segment between the two wax fillers forms a trimming segment; a wax spraying pipe, a wax suction pipe and a liquid injection pipe are provided on the horizontal mounting plate, the wax spraying pipe is used to spray an anti-corrosion wax layer onto the bottom wall and side walls of the trimming segment, a heating wire is provided at the lower pipe mouth of the wax suction pipe to melt the wax layer on the bottom wall of the trimming segment, and the liquid injection pipe is used to inject corrosive liquid into the mesh cell.

[0013] Each of the wax injection pipes is movably mounted horizontally on the horizontal mounting rod, and the distance between the two can be adjusted.

[0014] The horizontal mounting rod is provided with a T-shaped guide groove with an opening facing downward, and the guide movement in the T-shaped guide groove is installed on two movable rods. The upper end of the movable rod has a threaded section, and the threaded section is equipped with a locking nut. The lower end of each movable rod is provided with a pipe clamp for fixing the wax injection tube.

[0015] The upper end of the injection tube is provided with a Y-shaped joint, the first port of the upper end of the Y-shaped joint is used to connect to the aspirator, and the other port is connected to the injector.

[0016] A wax liquid tank is provided on the horizontal mounting plate. The wax liquid tank is connected to the wax spraying pipe through a first pipe, and is connected to two wax injection pipes through a second pipe and a third pipe respectively. Liquid injection pumps are provided on the first pipe, the second pipe and the third pipe. Electric heating wires are provided on the wax liquid tank and the first pipe, the second pipe and the third pipe to prevent the wax liquid from solidifying.

[0017] The injection pump is provided with an electric heating wire or is covered with a heat-insulating layer.

[0018] The horizontal mounting plate is provided with a wax recovery box, which is connected to the wax suction pipe through a fourth pipe. The fourth pipe is connected to an air duct, which is provided with a fan. The air duct and the fourth pipe form a venturi tube structure.

[0019] The crossbeam is provided with a T-slot, and the hanging frame is provided with a bolt movably installed in the T-slot, the head of the bolt is located in the T-slot, and the rod of the bolt passes through the T-slot upward and is equipped with a locking nut.

[0020] The present invention has the following beneficial effects: If the location requiring trimming is at the end of a cell, a wax filler can be placed on one side of that location, with the wax filler and the cell end forming a trimming section. If the location requiring trimming is in the middle of a cell, wax fillers can be placed on both sides of that location, with the cell section between the two wax fillers forming the trimming section. To prevent corrosive liquid from corroding the cell sidewalls, wax liquid is sprayed throughout the trimming section to form a corrosion-resistant wax layer on both the bottom and side walls of the trimming section. A heating wire on a wax suction pipe then melts the wax layer on the bottom wall of the trimming section and removes it from the cell. Corrosive liquid is then injected into the trimming section to corrode the bottom wall. Finally, hot water is used to clean all wax residue from the printing roller. During subsequent printing, the trimming section is more concave than the surrounding cells, storing more ink deeper. After printing, a convex portion higher than the surrounding portion is formed here to form an anti-counterfeiting mark. A series of continuous convex portions or multiple scattered convex portions can be designed to form an anti-counterfeiting mark. Moreover, the anti-counterfeiting mark is not easy to detect and imitate. Even if it is detected and imitated, the imitator needs to make a plate, especially a corrosion plate. The existing corrosion plate making method cannot perform local trimming again. However, the trimming method and trimming device of the present application can trim many places of the printing roller at any time. The imitator needs to find and make the plate again, which is very costly. Thus, a better anti-counterfeiting effect can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of an embodiment of a trimming device of the present invention;

[0022] Figure 2 yes Figure 1 A partial enlarged view of point A in the middle;

[0023] Figure 3 yes Figure 1 Schematic diagram of the structure at another angle;

[0024] Figure 4 yes Figure 3 A partial enlarged view of point B in the middle. DETAILED DESCRIPTION

[0025] To facilitate understanding of the present invention, the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0026] It should be noted that, unless otherwise defined, the technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0027] A method for trimming a gravure printing roller for anti-counterfeiting printing according to the present invention comprises the following steps:

[0028] 1) Wax fillers are placed on one or both sides of the cell positions where anti-counterfeiting is required. The wax fillers are used to block the cells on the corresponding side, so that the cell segment on one side of the wax filler or the cell segment between two wax fillers forms a trimming segment.

[0029] In this step, if the location to be trimmed is at the end of a cell, a wax filler can be placed on one side of that location. The cell segment between the wax filler and the cell end forms the trimming segment. If the location to be trimmed is in the middle of a cell, wax fillers can be placed on both sides of that location. The segment between the two wax fillers forms the trimming segment.

[0030] 2) Spraying an anti-corrosion wax layer onto the trimming section of step 1).

[0031] Since it is difficult to spray a wax layer onto the opposite side walls of the trimming section alone, this step in the present application allows wax liquid to be sprayed onto both the bottom wall and the side walls of the trimming section, and the wax liquid forms a wax layer.

[0032] 3) A wax suction pipe with a heating wire at the end is extended into the trimming section in step 2), the heating wire melts the wax layer on the bottom wall of the trimming section and the melted wax liquid is sucked away by the wax suction pipe.

[0033] 4) Injecting a corrosive liquid into the trimming section in step 3) to corrode the bottom wall of the trimming section.

[0034] In this step, the corresponding etching liquid is selected according to the material of the printing roller.

[0035] 5) After the set etching time, the gravure printing roller is rinsed with hot water above 50°C to clean the wax filling and wax layer thereon.

[0036] In this step, the etching time is set according to the desired etching depth. The hot water temperature can be selected as long as it can melt the wax on the printing roller and then be carried away by the water flow, such as 80 degrees, 90 degrees, or 100 degrees. The appropriate hot water temperature is also selected according to the type of wax used.

[0037] In this step, since the amount of injected corrosion liquid is limited, if one corrosion cannot achieve the corrosion effect, then after a certain period of corrosion, the corrosion liquid will be extracted and new corrosion liquid will be injected again. This process will be repeated more than twice until the desired corrosion effect is achieved.

[0038] A dressing device for implementing the above-mentioned dressing method for the gravure printing roller for anti-counterfeiting printing of the present invention is as follows: Figure 1-Figure 4 As shown, the apparatus comprises a frame 1 for rotatably mounting a printing roller 2 to be trimmed. A power mechanism 3, which is a motor, is mounted on the frame 1 to drive the printing roller 2. The frame 1 is provided with a driven shaft and a driving shaft, which are drivingly connected to the motor. Both the driven shaft and the driving shaft are rotatably mounted on the frame. The roller shafts fixed at both ends of the printing roller 2 to be trimmed are respectively connected to the driven shaft and the driving shaft via couplings. The motor drives the printing roller to rotate, thereby adjusting the rotation angle of the printing roller so that the cells to be trimmed face upward.

[0039] The device frame 1 comprises a base plate 28, vertical beams 29, and a top crossbeam 4. The printing roller 2 is rotatably mounted on two opposing vertical beams 29. The crossbeams 4 are positioned above the printing roller, with their lengths parallel to the roller's axis. During installation, the top ends of the vertical beams 29 are provided with U-shaped mounting slots 31. Rectangular mounting blocks 30 are positioned at each end of the crossbeam 4. These blocks 30 fit snugly into the U-shaped slots 31 and are secured to the U-shaped slots 31 by connecting bolts 32, facilitating installation and removal. Two or more trimming mechanisms 5 are removably mounted on the crossbeams 4, with the number of trimming mechanisms 5 equal to the number of patterns arranged in a single row along the axis of the printing roller. Each trimming mechanism 5 comprises a mounting bracket 6 removably mounted on the crossbeams. The crossbeams 4 are provided with T-slots 7, and bolts are mounted on the mounting brackets 6, which are movably mounted in the T-slots 7. The bolts' heads are positioned in the T-slots, while the shanks extend upward through the slots and are fitted with locking nuts 8. After adjustment, each trimming mechanism is located directly above the corresponding printing roller where the trimming is to be performed.

[0040] An electric telescopic rod 9 is provided on the hoisting frame 6. A horizontal mounting plate 10 is rotatably provided on the movable end 11 of the electric telescopic rod 9. A first gear 12 is provided on the movable end 11. A second gear 13 that cooperates with the first gear and a first drive motor 14 that drives the second gear are provided on the horizontal mounting plate 10. Power is transmitted between the first gear 12 and the second gear 13 via an intermediate gear 15. The setting of the intermediate gear allows for flexible adjustment of the positions of the second gear and the first drive motor to avoid interference between them. A horizontal mounting rod 16 is rotatably provided on the horizontal mounting plate 10. A second drive motor 17 that drives the horizontal mounting rod is provided on the horizontal mounting plate. Two wax injection tubes 18 are horizontally arranged relative to each other on the horizontal mounting rod. The wax injection tubes 18 are used to inject wax filler on one or both sides of the cell position where anti-counterfeiting is required, so that the cell segment on one side of the wax filler or the cell segment between two wax fillers forms a trimming section. The horizontal mounting rod 16 is provided with a downwardly opening T-shaped guide slot 28, which guides the movable mounting of two movable rods 19. The upper ends of the movable rods have threaded sections equipped with lock nuts 29. The lower ends of the movable rods are provided with pipe clamps 20 for securing the wax injection tubes. The two movable wax injection tubes 18 can be adjusted to the length of the trimming section as needed, making them convenient to use.

[0041] The horizontal mounting plate 10 is provided with a wax spraying pipe 21, a wax suction pipe 22, and a liquid injection pipe 23. The wax spraying pipe 21 is used to spray an anti-corrosion wax layer into the trimming section. The lower end of the wax suction pipe 22 is provided with a heating wire for melting the wax layer on the bottom wall of the mesh cells. The liquid injection pipe 23 is used to inject corrosive liquid into the mesh cells. In this embodiment, the upper end of the liquid injection pipe 23 is provided with a Y-shaped connector. The first port 24 of the Y-shaped connector is connected to a liquid suction device, and the other port 25 is connected to the liquid injection device, so as to recover the corrosive liquid. The horizontal mounting plate is provided with a wax liquid tank 26. The wax liquid tank 26 is connected to the wax spraying pipe 21 via a first pipe and to the two wax injection pipes 18 via a second pipe and a third pipe, respectively. The first pipe, the second pipe, and the third pipe are each provided with a liquid injection pump. The wax liquid tank and the first pipe, the second pipe, and the third pipe are all provided with electric heating wires to prevent the wax liquid from solidifying. The injection pump is equipped with a heating wire or a thermal insulation layer to prevent the wax from solidifying as it passes through the injection pump. A wax recovery tank 27 is provided on the horizontal mounting plate 10 and is connected to the wax suction pipe 22 via a fourth pipe. The fourth pipe is connected to an air duct equipped with a fan. The air duct and the fourth pipe form a Venturi structure. The fourth pipe is also equipped with a heating wire to ensure that the wax can enter the wax storage tank and prevent it from solidifying on the pipe wall and causing blockage. The fan can also blow hot air.

[0042] During use, the printing roller to be trimmed is mounted on the device frame and connected to a power mechanism. The power mechanism rotates the printing roller to adjust its position so that the cells in a row of patterns to be trimmed are directly above. The trimming mechanism is then adjusted to align with the cells below. The two wax injection pipes on all trimming mechanisms are then adjusted so that the distance between them equals the length of the cells to be trimmed. Liquid wax is injected into the cells below through the two wax injection pipes in conjunction with an electric push rod. The wax instantly solidifies in the cells, forming a wax filling. The cell segment between the two wax fillings forms the trimming section. If the cell segment to be trimmed is located at the end, only one wax injection pipe can be used. In this case, the trimming section is formed between the wax filling and the cell end. The horizontal mounting plate is then rotated to position the wax spray pipe above the trimming section. During platemaking, the cells typically have a T-shaped cross-section to ensure smooth ink removal from the printed material. Therefore, the wax spray pipe, coupled with an electric push rod, sprays wax onto the bottom and side walls of the trimming section, forming an anti-corrosion layer. The horizontal mounting plate is then rotated to position the wax suction pipe above the trimming section. The electric push rod is then used to extend a heating wire at the lower end of the wax suction pipe into the trimming section. The heating wire can have either a wavy or straight configuration. This heating wire melts the wax at the bottom of the trimming section, drawing it into the wax suction pipe through negative pressure. The horizontal mounting plate is then rotated to position the liquid injection pipe above the trimming section. The electric push rod is then used to inject corrosive liquid into the trimming section through the liquid injection pipe, corroding the bottom wall. The corrosive liquid is then recovered through the liquid injection pipe. Finally, place a sink on the bottom plate below the printing roller, and pour hot water on the printing roller to melt all the wax on it and rinse off the residual corrosive liquid, and then dry or bake the printing roller.

[0043] In the foregoing description of this specification, unless otherwise expressly specified or limited, terms such as "fixed," "mounted," "connected," or "connected" should be understood broadly. For example, the term "connected" can refer to a fixed connection, a removable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediary; or the internal connection between two components or the interaction between two components. Therefore, unless otherwise expressly defined in this specification, those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0044] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", "center", "longitudinal", "lateral", "clockwise" or "counterclockwise", etc., which indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the drawings of this specification, and are only for the purpose of facilitating the explanation of the scheme of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or element involved must have the specific orientation, be constructed and operate in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as limitations on the scheme of the present invention.

[0045] In addition, the terms "first" or "second" used in this specification to refer to numbers or ordinal numbers are used for descriptive purposes only and should not be understood as explicitly or implicitly indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this specification, "plurality" means at least two, such as two, three or more, etc., unless otherwise clearly specified.

[0046] In other embodiments of the present invention, in order to facilitate the adjustment of the positions of the wax suction tube, wax spray tube and liquid injection tube, the installation method of the liquid injection tube can be referred to, and a mounting rod is rotatably set on the horizontal mounting plate and a driving motor for driving the mounting rod to rotate is set on the horizontal mounting plate. The mounting rod and the driving motor correspond one to one and there are three of them, which are respectively arranged corresponding to the wax suction tube, wax spray tube and liquid injection tube. At this time, a T-shaped slot is provided on each mounting rod, and a movable rod is provided in each T-shaped slot for guiding movement. The upper end of the movable rod has a threaded section, and the threaded section is equipped with a locking nut. The lower end of each movable rod is provided with a pipe clamp for fixing the wax suction tube, wax spray tube and liquid injection tube.

Claims

1. A method for trimming a gravure printing roller for anti-counterfeiting printing, characterized in that: The following steps are included: 1) Wax fillers are placed on one or both sides of the cell locations where anti-counterfeiting is required. The wax fillers are used to block the cells on the corresponding side, so that the cell segment on one side of the wax filler or the cell segment between two wax fillers forms a trimming segment; 2) spraying an anti-corrosion wax layer into the trimming section of step 1); 3) inserting a wax suction pipe with a heating wire at the end into the trimming section in step 2), the heating wire melts the wax layer on the bottom wall of the trimming section and the wax suction pipe sucks away the melted wax liquid; 4) injecting a corrosive liquid into the trimming section in step 3) to corrode the bottom wall of the trimming section; 5) After the set etching time, the gravure printing roller is rinsed with hot water above 50°C to clean the wax filling and wax layer thereon.

2. The method for trimming a gravure printing roller for anti-counterfeiting printing according to claim 1, characterized in that: In step 5), after a certain period of corrosion, the corrosion liquid is extracted and new corrosion liquid is re-injected, and this process is repeated two or more times until the desired corrosion effect is achieved.

3. A dressing device capable of implementing the dressing method of the gravure printing roller for anti-counterfeiting printing according to claim 1, characterized in that: The invention comprises a device frame for rotatably mounting a printing roller to be trimmed, the device frame having a crossbeam located above the printing roller, the length direction of the crossbeam being parallel to the axis direction of the printing roller, and two or more trimming mechanisms being movably provided on the crossbeam; each trimming mechanism comprises a hanging frame movably mounted on the crossbeam, an electric telescopic rod being provided on the hanging frame, a horizontal mounting plate being rotatably provided on the movable end of the electric telescopic rod, a first gear being provided on the movable end, a second gear being transmitted to the first gear and a first driving motor driving the second gear to rotate; a horizontal mounting plate being rotatably provided on the horizontal mounting plate Rod, a second driving motor for driving the horizontal mounting rod to rotate is provided on the horizontal mounting plate, and two wax injection pipes are horizontally arranged on the horizontal mounting rod, which are used to inject wax filler on one side or both sides of the mesh cell position where anti-counterfeiting is required, so that the mesh cell segment on one side of the wax filler or the mesh cell segment between two wax fillers forms a trimming segment; a wax spraying pipe, a wax suction pipe and a liquid injection pipe are provided on the horizontal mounting plate, the wax spraying pipe is used to spray an anti-corrosion wax layer onto the bottom wall and side wall of the trimming segment, a heating wire is provided at the lower pipe mouth of the wax suction pipe to melt the wax layer on the bottom wall of the trimming segment, and the liquid injection pipe is used to inject corrosive liquid into the mesh cell.

4. The trimming device according to claim 3, characterized in that: Each of the wax injection pipes is movably mounted horizontally on the horizontal mounting rod, and the distance between the two can be adjusted.

5. The trimming device according to claim 4, characterized in that: The horizontal mounting rod is provided with a T-shaped guide groove with an opening facing downward, and the guide movement in the T-shaped guide groove is installed on two movable rods. The upper end of the movable rod has a threaded section, and the threaded section is equipped with a locking nut. The lower end of each movable rod is provided with a pipe clamp for fixing the wax injection tube.

6. The trimming device according to claim 3, characterized in that: The upper end of the injection tube is provided with a Y-shaped joint, the first port of the upper end of the Y-shaped joint is used to connect to the aspirator, and the other port is connected to the injector.

7. The trimming device according to claim 3, characterized in that: A wax liquid tank is provided on the horizontal mounting plate. The wax liquid tank is connected to the wax spraying pipe through a first pipe, and is connected to two wax injection pipes through a second pipe and a third pipe respectively. Liquid injection pumps are provided on the first pipe, the second pipe and the third pipe. Electric heating wires are provided on the wax liquid tank and the first pipe, the second pipe and the third pipe to prevent the wax liquid from solidifying.

8. The trimming device according to claim 7, characterized in that: The injection pump is provided with an electric heating wire or is covered with a heat-insulating layer.

9. The trimming device according to claim 3, characterized in that: The horizontal mounting plate is provided with a wax recovery box, which is connected to the wax suction pipe through a fourth pipe. The fourth pipe is connected to an air duct, which is provided with a fan. The air duct and the fourth pipe form a venturi tube structure.

10. The trimming device according to claim 9, characterized in that: The crossbeam is provided with a T-slot, and the hanging frame is provided with a bolt movably installed in the T-slot, the head of the bolt is located in the T-slot, and the rod of the bolt passes through the T-slot upward and is equipped with a locking nut.

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