Metal coin stamp impressing forming device

Abstract

The utility model discloses a metal coin stamp impressing forming device which comprises a base, the top of the base is fixedly connected with an impressing table, a containing cavity is formed in the impressing table, a recycling box is placed in the containing cavity, a plurality of through holes are formed in the top of the containing cavity, the top of the impressing table is fixedly connected with a baffle, and the baffle is fixedly connected with the bottom of the base. A plurality of threaded holes are formed in the surface of the baffle, a positioning screw is in threaded connection in each threaded hole, a support is arranged on the rear side of the imprinting table, a pair of pipe holes is formed in the top of the support, and an imprinting mechanism and a cleaning mechanism are arranged on the support. According to the metal coin stamping device, the surface of a metal blank can be cleaned before stamping forming, the stamping forming quality of a metal coin is guaranteed, the stamping template is convenient to disassemble, stamping patterns can be rapidly replaced, the whole device does not need to be replaced, cost is greatly reduced, and meanwhile regular maintenance of the stamping template is facilitated.

Description

Technical Field

[0001] The utility model belongs to the technical field of metal coin and medal processing, and particularly relates to a metal coin and medal embossing forming device. Background Technique

[0002] Metal coins and medals are usually simply referred to as commemorative coins or commemorative medals, and are a kind of commemorative object or collection made of metal. They are often used to commemorate specific events, people, places or organizations. The designs of metal coins and medals are usually very delicate, with certain collection value and artistic value.

[0003] The embossing forming of metal coins and medals is a common manufacturing process, which makes delicate metal coins and medals by embossing design patterns onto metal blanks. At present, there are some embossing devices on the market. For example, a surface embossing system for metal commemorative medals is disclosed on the Chinese Patent Network, with the publication number CN208498100U. This embossing system shortens the time required for loading and unloading, embosses automatically, and is manually inspected. The entire embossing step is accurate and rapid, with high embossing efficiency, and only requires workers to take materials, reducing the labor intensity of workers, thus realizing continuous embossing operations for metal commemorative medals and meeting the batch production requirements of commemorative medal products in strips. However, there are some defects and deficiencies to be improved: (1) Before the embossing forming of metal coins and medals, their surfaces often adhere to particulate impurities such as dust, and some existing embossing devices are difficult to clean the surfaces of metal coins and medals, so that these impurities always remain on the surfaces of metal coins and medals, thus affecting the quality of embossing forming; (2) Some existing embossing devices usually adopt an integrated design, and the embossing templates are often fixed on the devices and difficult to disassemble. When the embossing patterns need to be changed, only the whole device can be replaced, and the embossing templates cannot be replaced separately, thus increasing the cost and making it inconvenient to perform regular maintenance on the embossing templates. Therefore, in view of the above problems, it is of great significance to provide a metal coin and medal embossing forming device according to the present utility model. Summary of the Utility Model

[0004] The utility model provides a metal coin and medal embossing forming device. The cleaning mechanism can blow off particulate impurities such as dust adhering to the surface of the metal blank by wind force and recycle them through a recycling box, so as to clean the surface of the metal blank before embossing forming, avoiding the influence of impurities remaining on the surface of the metal coin and medal on the quality of embossing forming; the embossing template can be removed by unscrewing the nut, so as to quickly change the embossing pattern as needed without replacing the whole device, not only greatly reducing the cost of replacing the device, but also facilitating the regular maintenance of the embossing template. In summary, the problems in the background technique are solved.

[0005] To solve the above technical problems, the present utility model is realized through the following technical solutions:

[0006] A metal coin and medal stamping and forming device of the utility model includes a base. A stamping table is fixedly connected to the top of the base. A storage cavity is formed inside the stamping table. A recycling box is placed inside the storage cavity. A plurality of through holes are formed at the top of the storage cavity. A baffle is fixedly connected to the top of the stamping table. The baffle is annular, and a plurality of threaded holes are formed on its surface. A positioning screw is threadedly connected to each threaded hole. A bracket is arranged at the rear side of the stamping table. The side surface of the bracket is L-shaped, and its bottom is fixedly connected to the base. A pair of pipe holes are formed at the top of the bracket. A stamping mechanism and a cleaning mechanism are respectively arranged on the bracket.

[0007] The stamping mechanism includes a hydraulic cylinder. The hydraulic cylinder is installed on the inner wall of the top of the bracket. The bottom end of its output shaft is fixedly connected to a mounting seat. A stamping template is installed at the bottom of the mounting seat. The cross-section of the stamping template is circular, and a stamping pattern is arranged at its bottom. The stamping template is located directly above the stamping table.

[0008] The cleaning mechanism includes a hair dryer and a cleaning pipe. The hair dryer is installed on the top of the bracket, and air guide pipes are installed on both sides of it. The cleaning pipe is of an annular pipe structure. A plurality of fixing columns are fixedly connected between the top of the cleaning pipe and the bottom of the mounting seat. A plurality of air blowing openings are formed at the bottom of the cleaning pipe. Air inlet openings are formed on both sides of the cleaning pipe. The end openings of the air guide pipes pass through the pipe holes and are connected to the air inlet openings.

[0009] Further, the air blowing openings are evenly distributed in an annular shape along the circumferential direction of the cleaning pipe, and the top ends of the air blowing openings are communicated with the cleaning pipe.

[0010] Further, a plurality of mounting columns are fixedly connected to the top of the stamping template. External threads are engraved on the column bodies of the mounting columns and are threadedly connected with nuts that match them. A plurality of mounting holes are formed on the mounting seat. The number of the mounting holes is the same as that of the mounting columns, the diameters correspond equally, and the centers of each mounting hole and each mounting column correspond one by one.

[0011] Further, a layer of buffer pads is arranged on the end surface of each positioning screw.

[0012] Further, guide blocks are fixedly connected to the inner walls on both sides of the stamping table. A handle is fixedly connected to the front end surface of the recycling box. Guide grooves are formed on the outer walls on both sides of the recycling box. The guide grooves and the guide blocks are both rectangular. The width of the guide grooves corresponds equally to the thickness of the guide blocks, and the centers of each guide groove and each guide block correspond one by one.

[0013] Furthermore, heating elements are installed on both sides of the imprinting table. The heating element includes a heating chamber. Power supply bases are installed on both inner walls of the heating chamber. An electric heating wire is electrically connected between the power supply bases. Convex blocks are fixedly connected to both outer walls of the heating chamber. Positioning holes are formed on the surfaces of the convex blocks. Bolts are inserted into the positioning holes. A number of threaded grooves matching the bolts are formed on the surfaces of both outer walls of the imprinting table. The diameters of the threaded grooves and the positioning holes are correspondingly equal, and the centers of each threaded groove and each positioning hole correspond to each other one by one.

[0014] Furthermore, a number of anti-slip pads are arranged on the bottom surface of the base. The anti-slip pads are linearly distributed at equal intervals along the length direction of the base, and herringbone anti-slip patterns are engraved on the surface of each anti-slip pad.

[0015] The present utility model has the following beneficial effects compared with the prior art:

[0016] (1) When the metal coin and medal imprinting and forming device in the present utility model is in use, through the cleaning mechanism, dust and other particulate impurities adhered to the surface of the metal blank can be blown away by wind and recycled through the recycling box, so as to clean the surface of the metal blank before imprinting and forming, avoiding the influence of impurities remaining on the surface of the metal coin and medal on the quality of imprinting and forming;

[0017] (2) When the metal coin and medal imprinting and forming device in the present utility model is in use, the imprinting template can be removed by unscrewing the nut, so as to quickly replace the imprinting pattern according to needs, without replacing the entire device, which not only greatly reduces the cost of replacing the device, but also facilitates regular maintenance of the imprinting template.

[0018] Of course, it is not necessary for any product implementing the present utility model to achieve all the above-mentioned advantages simultaneously. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a schematic structural diagram of a metal coin and medal imprinting and forming device of the present utility model;

[0021] Figure 2 It is a schematic structural diagram of the base and the imprinting table in the present utility model;

[0022] Figure 3 It is a bottom view of the base in the present utility model;

[0023] Figure 4 It is a schematic structural diagram of the cleaning mechanism in the present utility model;

[0024] Figure 5 It is a schematic structural diagram of the mounting base in the present utility model;

[0025] Figure 6 It is a schematic structural diagram of the stamping template in the present utility model;

[0026] Figure 7 It is a schematic structural diagram of the positioning screw in the present utility model;

[0027] Figure 8 It is a schematic structural diagram of the recycling box in the present utility model;

[0028] Figure 9 It is a schematic structural diagram of the heating element in the present utility model.

[0029] In the attached drawings, the list of components represented by each label is as follows:

[0030] 1. Base; 2. Stamping table; 3. Storage cavity; 4. Recycling box; 5. Through hole; 6. Baffle; 7. Threaded hole; 8. Positioning screw; 9. Bracket; 10. Pipe hole; 11. Hydraulic cylinder; 12. Mounting base; 13. Stamping template; 14. Hair dryer; 15. Cleaning pipe; 16. Air duct; 17. Fixed column; 18. Air outlet; 19. Air inlet; 20. Mounting column; 21. Nut; 22. Mounting hole; 23. Buffer pad; 24. Guide block; 25. Handle; 26. Guide groove; 27. Heating chamber; 28. Power supply base; 29. Electric heating wire; 30. Protrusion; 31. Positioning hole; 32. Bolt; 33. Threaded groove; 34. Anti-slip pad. Specific embodiments

[0031] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the attached drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0032] In the description of the present utility model, it should be understood that the terms "relative", "one end", "inner", "lateral", "end", "both ends", "both sides", "front", "one end face", "the other end face", etc. indicating the orientation or position relationship are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model.

[0033] Please refer to Figures 1-9 As shown, a metal coin and medal embossing and forming device of the present utility model includes a base 1. A stamping table 2 is fixedly connected to the top of the base 1. A receiving cavity 3 is formed inside the stamping table 2. A recycling box 4 is placed inside the receiving cavity 3. A plurality of through holes 5 are formed at the top of the receiving cavity 3. A baffle 6 is fixedly connected to the top of the stamping table 2. The baffle 6 is annular, and a plurality of threaded holes 7 are formed on its surface. A positioning screw 8 is threadedly connected to each threaded hole 7. After the metal blank is placed on the stamping table 2, by tightening the positioning screw 8, it can be tightly pressed against the side wall of the metal blank. At this time, the metal blank can be clamped and fixed by a plurality of positioning screws 8. A bracket 9 is arranged at the rear of the stamping table 2. The side of the bracket 9 is L-shaped, and its bottom is fixedly connected to the base 1. A pair of pipe holes 10 are formed at the top of the bracket 9. An embossing mechanism and a cleaning mechanism are respectively arranged on the bracket 9;

[0034] The embossing mechanism includes a hydraulic cylinder 11. The hydraulic cylinder 11 is installed on the inner wall of the top of the bracket 9. The bottom end of its output shaft is fixedly connected to a mounting seat 12. An embossing template 13 is installed at the bottom of the mounting seat 12. The cross-section of the embossing template 13 is circular, and an embossing pattern is arranged at its bottom. The embossing template 13 is located directly above the stamping table 2. By driving the hydraulic cylinder 11, the mounting seat 12 can be driven to move downward together with the embossing template 13. When the embossing template 13 contacts the metal blank, the pattern at the bottom of the embossing template 13 can be pressed into the metal blank by the pressure applied by the hydraulic cylinder 11, thereby completing the embossing and forming of the metal coin and medal;

[0035] The cleaning mechanism includes a hair dryer 14 and a cleaning pipe 15. The hair dryer 14 is installed on the top of the bracket 9, and air ducts 16 are installed on both sides thereof. The cleaning pipe 15 is of an annular pipe structure. A number of fixing columns 17 are fixedly connected between the top of the cleaning pipe 15 and the bottom of the mounting seat 12. A number of air blowing ports 18 are provided at the bottom of the cleaning pipe 15, and air inlets 19 are provided on both sides of the cleaning pipe 15. The end ports of the air ducts 16 pass through the pipe holes 10 and are connected to the air inlets 19. The air ducts 16 are made of soft plastic pipes with good elasticity and can be stretched and bent. Before stamping and forming the metal blank, the hydraulic cylinder 11 is driven to drive the mounting seat 12 and the cleaning pipe 15 to move downward together until the cleaning pipe 15 moves above the metal blank. Then the hair dryer 14 is started to blow air. At this time, the air can be introduced into the cleaning pipe 15 through the air ducts 16 and the air inlets 19 and blown to the surface of the metal blank through the respective air blowing ports 18, so that the particulate impurities such as dust adhering to the surface of the metal blank can be blown away by the wind, so as to complete the cleaning treatment of the metal blank. The blown impurities can pass through the through holes 5 into the storage cavity 3 and fall into the recycling box 4, so that the impurities can be recycled uniformly through the recycling box 4. The recycling box 4 can be pulled out of the storage cavity 3 by holding the handle 25 to facilitate the subsequent treatment of the impurities in the recycling box 4.

[0036] Among them, the air blowing ports 18 are evenly distributed in an annular shape along the circumferential direction of the cleaning pipe 15, and their tops are communicated with the cleaning pipe 15. Through the multiple annularly distributed air blowing ports 18, the blowing range of the cleaning pipe 15 can be effectively expanded, so that the air blown out by the hair dryer 14 can fully cover the surface of the metal blank, thereby improving the cleaning efficiency and effect.

[0037] Among them, a number of mounting columns 20 are fixedly connected to the top of the stamping template 13. External threads are engraved on the column bodies of the mounting columns 20 and are threadedly connected with nuts 21 that match them. A number of mounting holes 22 are provided on the mounting seat 12. The number of the mounting holes 22 is the same as that of the mounting columns 20, and the diameters correspond equally. And the centers of each mounting hole 22 and the centers of each mounting column 20 correspond one by one. Each mounting column 20 can be aligned and pass through the corresponding mounting hole 22. At this time, the nuts 21 are threadedly connected to each mounting column 20 and tightened. The stamping template 13 can be fixed on the mounting seat 12 through the mutual cooperation among the mounting columns 20, the mounting holes 22 and the nuts 21. By unscrewing the nuts 21, the stamping template 13 can be removed, so as to quickly replace the stamping pattern according to needs without replacing the entire equipment, which not only greatly reduces the cost of replacing the equipment, but also facilitates the regular maintenance of the stamping template 13.

[0038] Among them, a layer of buffer pads 23 is provided on the end surface of each positioning screw 8. The buffer pads 23 are made of elastic materials such as rubber and are fixed by means of glue. When the positioning screw 8 abuts against the side wall of the metal blank, the buffer pads 23 can play a role in buffering and protection, so as to avoid damage to the surface of the metal blank due to excessive clamping force of the positioning screw 8.

[0039] Among them, guide blocks 24 are fixedly connected to the inner walls on both sides of the embossing table 2. A handle 25 is fixedly connected to the front end surface of the recycling box 4. Guide grooves 26 are formed on the outer walls on both sides thereof. Both the guide grooves 26 and the guide blocks 24 are rectangular. The groove width of the guide grooves 26 corresponds to the thickness of the guide blocks 24, and the centers of each of the guide grooves 26 and the centers of each of the guide blocks 24 correspond one by one. When the recycling box 4 is placed in the storage cavity 3, the guide blocks 24 can fit into the guide grooves 26. At this time, the recycling box 4 can be limited by the mutual cooperation between the guide blocks 24 and the guide grooves 26, so as to avoid the placement position of the recycling box 4 shifting and affecting the recycling of impurities.

[0040] Among them, heating elements are installed on both sides of the embossing table 2. The heating elements include heating chambers 27. Power supply seats 28 are installed on the inner walls on both sides of the heating chambers 27. A heating wire 29 is electrically connected between the power supply seats 28. Protrusions 30 are fixedly connected to the outer walls on both sides of the heating chambers 27. Positioning holes 31 are formed on the surfaces of the protrusions 30. Bolts 32 are inserted into the positioning holes 31. A number of threaded grooves 33 that cooperate with the bolts 32 are formed on the surfaces of the outer walls on both sides of the embossing table 2. The diameters of the threaded grooves 33 and the positioning holes 31 correspond to each other, and the centers of each of the threaded grooves 33 and the centers of each of the positioning holes 31 correspond one by one. By tightening the bolts 32 in the positioning holes 31, the ends thereof can be screwed into the corresponding threaded grooves 33. At this time, the heating chambers 27 can be fixed to the outer walls of the embossing table 2 through the mutual cooperation between the bolts 32 and the threaded grooves 33. The power supply seats 28 can supply power to the heating wire 29. After the heating wire 29 is energized, it can generate heat. The embossing table 2 can be made of a metal material with strong heat conduction performance, so as to absorb the heat generated by the heating wire 29 and transfer the heat to the metal blank, so that the metal blank can be heated during embossing to improve the ductility and workability of the metal blank.

[0041] Among them, a number of anti-slip pads 34 are provided on the bottom surface of the base 1. The anti-slip pads 34 are linearly distributed at equal intervals along the length direction of the base 1, and herringbone anti-slip patterns are engraved on the surface of each anti-slip pad 34. When the embossing forming device is placed on a smooth plane, the anti-slip patterns on the surfaces of the anti-slip pads 34 can be used to increase the friction between the base 1 and the contact surface, so as to play an anti-slip role, thereby effectively preventing the device from slipping and displacing during use.

[0042] The circuits, electronic components, and chip modules involved in the present utility model are all prior arts and can be fully realized by those skilled in the art without further elaboration. The content protected by the present utility model does not involve improvements to software and methods either.

[0043] The standard parts used in the application documents can all be purchased from the market. All components in the present application documents can be customized according to the descriptions in the specifications and drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts, and equipment all adopt conventional models in the prior art. The electrical components described in this text are all electrically connected to the external main controller and the 220V mains power supply, and the main controller can be a conventional known device such as the LED lamp body to play a control role.

[0044] The working principle of the present utility model is:

[0045] When the present utility model is in use, first, all the electrical components in the device are externally connected to a control switch and a power supply through wires. Then, the metal blank to be embossed is placed on the embossing table 2, and the positioning screws 8 in each threaded hole 7 on the surface of the baffle 6 are tightened until the end of the positioning screw 8 tightly abuts against the side wall of the metal blank, so as to clamp and fix the metal blank through multiple positioning screws 8. Then, the hydraulic cylinder 11 is driven to drive the mounting seat 12 and the cleaning pipe 15 to move downward together until the cleaning pipe 15 moves above the metal blank. Then, the blower 14 is started to blow air. At this time, the air can be introduced into the cleaning pipe 15 through the air duct 16 and the air inlet 19, and blown to the surface of the metal blank through each air outlet 18, so that the particulate impurities such as dust adhering to the surface of the metal blank can be blown away by the wind, so as to complete the cleaning treatment of the metal blank. The blown impurities can pass through the through holes 5 into the storage cavity 3 and fall into the recycling box 4, so as to uniformly recycle the impurities through the recycling box 4. When the surface cleaning of the metal blank is completed, the hydraulic cylinder 11 is driven to drive the mounting seat 12 and the embossing template 13 to move downward together until the embossing template 13 contacts the metal blank. At this time, the pattern at the bottom of the embossing template 13 can be pressed into the metal blank by the pressure applied by the hydraulic cylinder 11, so as to complete the embossing of the metal coin. During the embossing process, the power supply seat 28 in the heating chamber 27 can supply power to the heating wire 29. After the heating wire 29 is energized, heat can be generated. The embossing table 2 can be made of a metal material with strong thermal conductivity, so as to absorb the heat generated by the heating wire 29 and transfer the heat to the metal blank, so that the metal blank can be heated during embossing to improve the ductility and workability of the metal blank. By unscrewing the nut 21, the embossing template 13 can be removed, so as to quickly replace the embossing pattern according to needs without replacing the entire device, which not only greatly reduces the cost of replacing the device, but also facilitates the regular maintenance of the embossing template 13.

[0046] The preferred embodiments of the present utility model disclosed above are only used to help illustrate the present utility model. The preferred embodiments do not describe all the details in detail, nor do they limit the present utility model to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present utility model, so that those skilled in the relevant technical fields can well understand and utilize the present utility model. The present utility model is only limited by the claims and their full scope and equivalents.

Claims

1. A metal coin and medal stamping and forming device, characterized in that, It includes a base, on the top of which is fixedly connected an embossing table. An accommodation cavity is formed inside the embossing table, and a recycling box is placed in the accommodation cavity. A number of through holes are provided at the top of the accommodation cavity. A baffle is fixedly connected to the top of the embossing table. The baffle is annular, and a number of threaded holes are formed on its surface. A positioning screw is threadedly connected in each threaded hole. A bracket is arranged at the rear side of the embossing table. The side surface of the bracket is L-shaped, and its bottom is fixedly connected to the base. A pair of pipe holes are provided at the top of the bracket. An embossing mechanism and a cleaning mechanism are respectively arranged on the bracket; The embossing mechanism includes a hydraulic cylinder, which is installed on the inner wall of the top of the bracket. The bottom end of its output shaft is fixedly connected with a mounting seat. A pressing template is installed at the bottom of the mounting seat. The cross-section of the pressing template is circular, and an embossing pattern is arranged at its bottom. And the pressing template is located directly above the embossing table; The cleaning mechanism includes a hair dryer and a cleaning pipe. The hair dryer is installed on the top of the bracket, and air guide pipes are installed on both sides of it. The cleaning pipe is of an annular pipe structure. A number of fixing columns are fixedly connected between the top of the cleaning pipe and the bottom of the mounting seat. A number of air blowing ports are provided at the bottom of the cleaning pipe. And air inlet openings are provided on both sides of the cleaning pipe. The end pipe orifices of the air guide pipes pass through the pipe holes and are connected to the air inlet openings.

2. The metal coin and medal stamping and forming device according to claim 1, characterized in that, The air blowing ports are evenly distributed in an annular shape along the circumferential direction of the cleaning pipe, and their tops are communicated with the cleaning pipe.

3. A metal coin and medal stamping and forming device according to claim 1, characterized in that, A number of mounting columns are fixedly connected to the top of the pressing template. External threads are engraved on the column bodies of the mounting columns and are threadedly connected with nuts matching them. A number of mounting holes are provided on the mounting seat. The number of the mounting holes is the same as that of the mounting columns, and their diameters correspond equally. And the center of each mounting hole corresponds to the center of each mounting column one by one.

4. The metal coin and medal stamping and forming device according to claim 1, characterized in that, A layer of buffer pads is arranged on the surface of the end of each positioning screw.

5. A metal coin and medal stamping and forming device according to claim 1, characterized in that, Guide blocks are fixedly connected to the inner walls on both sides of the embossing table. A handle is fixedly connected to the front end face of the recycling box. Guide grooves are provided on both outer walls of it. The guide grooves and the guide blocks are both rectangular. The groove width of the guide grooves corresponds equally to the thickness of the guide blocks. And the center of each guide groove corresponds to the center of each guide block one by one.

6. The embossing forming device for metal coins and medals according to claim 1, characterized in that, Heating elements are installed on both sides of the embossing table. The heating element includes a heating chamber. Power supply seats are installed on the inner walls on both sides of the heating chamber. An electric heating wire is electrically connected between the power supply seats. Protrusions are fixedly connected to the outer walls on both sides of the heating chamber. Positioning holes are formed on the surfaces of the protrusions. Bolts are inserted into the positioning holes. A number of threaded grooves matching the bolts are formed on the surface of the outer wall on both sides of the embossing table. The diameters of the threaded grooves correspond equally to those of the positioning holes. And the center of each threaded groove corresponds to the center of each positioning hole one by one.

7. A metal coin and medal stamping and forming device according to claim 1, characterized in that, A number of anti-slip pads are arranged on the bottom surface of the base. The anti-slip pads are linearly distributed at equal intervals along the length direction of the base. And herringbone anti-slip patterns are engraved on the surface of each anti-slip pad.

Images