A staple bed

Abstract

The staple bed provided in this application includes a table, a first positioning pin, a second positioning pin, a lifting mechanism, and a drive assembly. The lifting mechanism includes a first lifting component and a second lifting component that are not co-located. A first actuating element of the first lifting component can push the first positioning pin upward, and a second actuating element of the second lifting component can push the second positioning pin upward. The drive assembly drives the first lifting component and the second lifting component to move between the front and rear ends of the table. This solves the problem of providing a stable and rapid lifting mechanism for a staple bed with high-density pins.

Description

Technical Field

[0001] This invention relates to the field of PCB board solder resist ink coating technology, and in particular to a nail bed. Background Technology

[0002] A bed of nails is used in the process of applying solder resist ink to PCB boards.

[0003] The bed of nails uses a special structural design of conical positioning pins (or ejector pins) to achieve suspended support of the PCB board, thereby preventing solder resist ink from sticking to the table surface. The positioning pins have raised and lowered states. A drive component (usually a cylinder) drives an actuating component (such as a movable column) to push the positioning pins upward, thus switching between the raised and lowered states.

[0004] Ink coating of the PCB board occurs before the breaking and segmentation process. A single PCB board can be divided into multiple smaller pieces. During ink coating, the entire PCB board is coated. The position where the PCB board is lifted by the positioning pins is the adjacent junction of the smaller PCB pieces; this is the edge of the finished smaller PCB piece and does not require ink coating. The adjacent junction positions differ relative to the bed of nails for PCBs of different sizes, therefore a denser arrangement of pins is needed to accommodate a wider range of PCB sizes.

[0005] While this approach solves the problem of adapting to a wider variety of PCB boards, it also introduces other issues. The denser the ejector pins, the smaller the installation space for the lifting mechanism below them. The lifting mechanism, in turn, needs to meet requirements such as sufficient support capacity, resistance to deformation, and stability. If the lifting mechanism is set up in a one-to-one correspondence with the ejector pins, the denser the ejector pins and the denser the lifting mechanism, the smaller the installation space for a single lifting mechanism. This necessitates the use of smaller lifting mechanisms, making it more difficult to meet these basic requirements.

[0006] Therefore, there are still problems in the existing technology that need to be solved. Summary of the Invention

[0007] The main objective of this invention is to provide a nail bed that addresses how to provide a stable and rapid lifting mechanism for a nail bed with high-density pins.

[0008] To achieve the above objectives, the present invention proposes a nail bed comprising: a table surface having a plurality of first pin holes and a plurality of second pin holes arranged in columns and rows, with the first pin holes located in odd-numbered columns and the second pin holes located in even-numbered columns; a first positioning pin disposed in a first pin hole; a second positioning pin disposed in a second pin hole; both the first and second positioning pins having raised and lowered states; and a lifting mechanism comprising a first lifting assembly and a second lifting assembly not arranged in the same row; the first lifting assembly comprising a plurality of first actuating elements arranged in a row, the first actuating elements being located at... Below the first positioning pin, a mechanism is used to push the first positioning pin upward, so that the first positioning pin switches between a raised state and a lowered state; the second lifting assembly includes a plurality of second actuators arranged in a row; the second actuators are located below the second positioning pins and are used to push the second positioning pins upward, so that the second positioning pins switch between a raised state and a lowered state; a driving assembly is used to drive the first lifting assembly and the second lifting assembly to move between opposite front and rear ends of the platform, so that the first positioning pin can be pushed upward by the first actuator and the second positioning pin can be pushed upward by the second actuator.

[0009] Preferably, the nail bed further includes multiple detection elements; the detection elements are used to detect the state of the first or second positioning pin from below the first or second positioning pin; the detection elements can move between the opposite front and rear ends of the table.

[0010] Preferably, the lifting mechanism further includes a mounting component, on which a first lifting assembly, a second lifting assembly, and a detection component are disposed; the driving assembly includes a first slide rail and a driving component, on which the mounting component is disposed; the driving component is used to drive the mounting component to move between the front and rear ends of the platform.

[0011] Preferably, the detection element includes a distance sensor for detecting the distance between itself and the lower end of the first positioning pin or the lower end of the second positioning pin.

[0012] Preferably, multiple testing components are arranged in a row.

[0013] Preferably, there are multiple sets of first lifting components, which are parallel to each other.

[0014] Preferably, the multiple sets of first lifting components can move from the front end to the rear end of the platform, or the multiple sets of first lifting components can move from the rear end to the front end of the platform.

[0015] Preferably, there are two sets of first lifting components. One set of first lifting components can move from the front end of the table to the middle of the table, and the other set of first lifting components can move from the rear end of the table to the middle of the table.

[0016] Preferably, multiple sets of first lifting components can move synchronously.

[0017] Preferably, a protective element is provided on the table surface, and a third pin hole is provided on the protective element for at least part of the first positioning pin or the second positioning pin to pass through; the protective element is a magnetic element; a magnet is provided on the table surface, or a magnet is provided near the table surface, and the protective element is attracted to the table surface by the magnet.

[0018] Preferably, multiple protective components are provided, and the multiple protective components are laid and spliced ​​on the table surface.

[0019] Preferably, the nail bed further includes multiple positioning mechanisms, each positioning mechanism including a fixed base, a first positioning pin and / or a second positioning pin, the first positioning pin and / or the second positioning pin being disposed on the fixed base; the multiple positioning mechanisms are detachably spliced ​​and laid on the nail bed.

[0020] Preferably, the first positioning pin and the second positioning pin include a sleeve and a shaft, with the sleeve fitted onto the shaft. The shaft of the first positioning pin can move relative to the sleeve of the first positioning pin under the push of the first actuating element; the shaft of the second positioning pin can move relative to the sleeve of the second positioning pin under the push of the second actuating element. A protruding post is formed radially extending from the side of the shaft, and a locking hole is formed in the sleeve, with the protruding post passing through the locking hole. The locking hole includes a plurality of first locking portions, a plurality of second locking portions, and a guide portion, with the plurality of first locking portions and the plurality of second locking portions alternately arranged along the circumference of the sleeve. The guide portion is used to guide the protruding post to move from the first locking portion to the adjacent second locking portion, or to guide the protruding post to move from the second locking portion to the adjacent first locking portion.

[0021] Preferably, the sleeve has a plurality of first teeth and a plurality of second teeth, the first teeth protruding upwards and the second teeth protruding downwards; a locking hole is formed between the first teeth and the second teeth; the first teeth face the groove between adjacent second teeth; the groove between adjacent first teeth forms a first locking part or a second locking part; the sidewall of the groove between adjacent second teeth and / or the sidewall of the first teeth at least partially forms a guide part.

[0022] Preferably, the second locking portion includes a downwardly extending sub-groove.

[0023] The nail bed provided in this embodiment includes a table, a first positioning pin, a second positioning pin, a lifting mechanism, and a drive assembly. The lifting mechanism includes a first lifting component and a second lifting component that are not co-located. A first actuating element of the first lifting component can push the first positioning pin upward, and a second actuating element of the second lifting component can push the second positioning pin upward. The drive assembly drives the first lifting component and the second lifting component to move between the front and rear ends of the table. This solves the problem of providing a stable and rapid lifting mechanism for a nail bed with high-density pins. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of an embodiment of the nail bed of the present invention;

[0026] Figure 2 This is another schematic diagram of an embodiment of the nail bed of the present invention; Figure 3 for Figure 2 Enlarged view of part A; Figure 4 This is another schematic diagram of an embodiment of the nail bed of the present invention; Figure 5 This is a schematic diagram of the lifting mechanism of an embodiment of the nail bed of the present invention; Figure 6 for Figure 5 An enlarged view of part B; Figure 7 This is a schematic diagram of the positioning mechanism of an embodiment of the nail bed of the present invention; Figure 8 This is a schematic diagram of a first or second positioning pin in an embodiment of the nail bed of the present invention.

[0027] Explanation of icon numbers:

[0028] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0029] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0031] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0032] A bed of nails is used in the process of applying solder resist ink to PCB boards.

[0033] The bed of nails uses a special structural design of conical positioning pins (or ejector pins) to achieve suspended support of the PCB board, thereby preventing solder resist ink from sticking to the table surface. The positioning pins have raised and lowered states. A drive component (usually a cylinder) drives an actuating component (such as a movable column) to push the positioning pins upward, thus switching between the raised and lowered states.

[0034] Ink coating of the PCB board occurs before the breaking and segmentation process. A single PCB board can be divided into multiple smaller pieces. During ink coating, the entire PCB board is coated. The position where the PCB board is lifted by the positioning pins is the adjacent junction of the smaller PCB pieces; this is the edge of the finished smaller PCB piece and does not require ink coating. The adjacent junction positions differ relative to the bed of nails for PCBs of different sizes, therefore a denser arrangement of pins is needed to accommodate a wider range of PCB sizes.

[0035] While this approach solves the problem of adapting to a wider variety of PCB boards, it also introduces other issues. The denser the ejector pins, the smaller the installation space for the lifting mechanism below them. The lifting mechanism, in turn, needs to meet requirements such as sufficient support capacity, resistance to deformation, and stability. If the lifting mechanism is set up in a one-to-one correspondence with the ejector pins, the denser the ejector pins and the denser the lifting mechanism, the smaller the installation space for a single lifting mechanism. This necessitates the use of smaller lifting mechanisms, making it more difficult to meet these basic requirements.

[0036] To address the aforementioned issues, this patent provides a nail bed designed to provide a stable and rapid lifting mechanism for a nail bed with high-density pins.

[0037] For ease of understanding, the specific implementation methods of the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0038] Please see Figure 1-7A nail bed includes: a table surface having a plurality of first pin holes and a plurality of second pin holes, the first pin holes and second pin holes being arranged in columns and rows, with the first pin holes located in odd-numbered columns and the second pin holes located in even-numbered columns; a first positioning pin disposed in a first pin hole; a second positioning pin disposed in a second pin hole; both the first and second positioning pins having a raised state and a lowered state; a lifting mechanism including a first lifting component and a second lifting component not arranged in a row; the first lifting component including a plurality of first actuating members arranged in a row, the first actuating members being located below the first positioning pins and used to push the first positioning pins upward, so that the first positioning pins switch between the raised state and the lowered state; the second lifting component including a plurality of second actuating members arranged in a row; the second actuating members being located below the second positioning pins and used to push the second positioning pins upward, so that the second positioning pins switch between the raised state and the lowered state; and a driving component for driving the first lifting component and the second lifting component to move between opposite front and rear ends of the table surface, so that the first positioning pins can be pushed upward by the first actuating members and the second positioning pins can be pushed upward by the second actuating members.

[0039] In this implementation, the first and second pinholes are distributed column-by-column, creating a matrix-like or near-matrix-like pinhole array on the platform (e.g., a matrix-like pinhole array with missing corners). In this application... Figure 3 The 05 marked in the middle represents row 1. Figure 3 The column marked 06 is the column number.

[0040] The odd and even columns can be determined by counting sequentially from the left end to the right end of the platform, or by counting sequentially from the right end to the left end of the platform. When the first and second positioning pins are pushed upwards from below by the device, the first and second positioning pins will switch between a raised state and a lowered state. In this embodiment, the first and second lifting components are not arranged in the same row, and the first actuating element is located on the line containing the odd-numbered columns, while the second actuating element is located on the line containing the even-numbered columns. This causes the first and second actuating elements arranged in a row to be misaligned, and the actuating elements that lift the positioning pins of adjacent columns are misaligned. In a high-density positioning pin bed, more space can be utilized, and larger, stronger actuating elements can be used to ensure the stability of the actuating elements in the high-density bed. Alternatively, while maintaining structural strength, a higher density of positioning pins can be arranged, allowing the bed to adapt to more PCB board sizes. Furthermore, the two sets of lifting components are used to lift some of the positioning pins, so that the lifting components can complete the lifting or lowering of the positioning pins of the entire nail bed with just one movement under the nail bed. When it is necessary to switch between different specifications of PCB boards, the switching time of the positioning pins of the nail bed is also very short, ensuring the continuity of the production line.

[0041] Building upon the above implementation, a further issue arises: how to determine the states of the first and second positioning pins. To address this issue, this embodiment provides the following implementation. Please refer to... Figure 5-6 The nail bed also includes multiple detection elements; the detection elements are used to detect the state of the first or second positioning pin from below the first or second positioning pin; the detection elements can move between the front and rear ends of the table.

[0042] Furthermore, the movement of the first lifting assembly, the second lifting assembly, and the detection element can be implemented in various ways; this embodiment provides the following implementation method. Please refer to [link / reference]. Figure 4-6 The lifting mechanism also includes a mounting component, a first lifting assembly, a second lifting assembly, and a detection component disposed on the mounting component; the drive assembly includes a first slide rail and a drive component, with the mounting component disposed on the first slide rail; the drive component is used to drive the mounting component to move between the front and rear ends of the platform.

[0043] Furthermore, multiple detection components can be configured in various ways; this embodiment provides the following implementation method. Please refer to [link / reference]. Figure 6 Multiple detection components are arranged in a row. This embodiment does not limit the location of the detection components arranged in a row. Preferably, the mounting component can be sequentially arranged with one row of detection components, one row of first actuating components, one row of second actuating components, and another row of detection components. In this way, when the mounting component moves between the front and rear ends of the table, after the first and second actuating components push the first and second positioning pins of a certain row, the detection components can immediately detect the first and second positioning pins of that row, thereby improving the working efficiency of the nail bed.

[0044] It should be noted that the detection component can be implemented in various ways, and this embodiment provides the following implementation. The detection component includes a distance sensor (not shown in the figure), which is used to detect the distance between itself and the lower end of the first positioning pin or the lower end of the second positioning pin.

[0045] It should be noted that both the first and second lifting components can be configured in multiple groups to improve the efficiency of pushing the positioning pin. For convenience, this embodiment uses the first lifting component as an example. There are multiple groups of first lifting components, and they are parallel to each other. In this implementation, different groups of first lifting components can have different movement ranges. For example, two groups of first lifting components can be configured, one group moving from the front end of the platform to the middle, and the other group moving from the middle to the rear end. To further improve efficiency, this embodiment provides the following implementation method. Please refer to... Figure 1-2 Multiple sets of first lifting components can move from the front end to the rear end of the platform, or multiple sets of first lifting components can move from the rear end to the front end of the platform.

[0046] In addition to the implementation methods described above, this embodiment also provides the following implementation methods. Please refer to [link / reference]. Figure 1-2 There are two sets of first lifting components. One set of first lifting components can move from the front end of the table to the middle of the table, and the other set of first lifting components can move from the rear end of the table to the middle of the table. This implementation method can also further improve the efficiency of changing the state of the positioning pin.

[0047] In an implementation where there are multiple sets of first lifting components, to further improve efficiency, the multiple sets of first lifting components can move synchronously. For example, the first lifting components can be set to two sets. While one set of first lifting components moves from the front end of the table to the middle of the table, the other set of first lifting components moves from the middle of the table to the back end of the table.

[0048] It should be noted that during the use of the nail bed, ink drips onto the work surface are inevitable. To facilitate cleaning and maintenance, save time, and reduce the impact on the continuity of production line operations, this embodiment provides the following implementation method. Please refer to... Figure 1-2 The table surface is covered with a protective element, which has a third pinhole for at least part of the first or second positioning pin to pass through. The protective element is magnetic. A magnet is located on the table surface, or near the table surface, and the protective element is attracted to the table surface by the magnet. In this implementation, the magnetic element can be a magnet or a metal component that can be attracted by a magnet. After the nail bed stops working, the user can remove the protective element, which may be stained with ink, for cleaning. Further details can be found in [link to relevant documentation]. Figure 2 Multiple protective components are installed and joined together on the countertop. Users can remove the protective components with ink residue for cleaning, while those without ink residue do not need to be cleaned.

[0049] It should be noted that, to facilitate maintenance of the positioning pin, this embodiment provides the following implementation method. Please refer to [link / reference]. Figure 7 The nail bed also includes multiple positioning mechanisms, each comprising a fixed base, a first positioning pin, and / or a second positioning pin, the first and / or second positioning pins being mounted on the fixed base. These multiple positioning mechanisms are detachably assembled and laid on the nail bed. In this implementation, since the positioning mechanisms can be detached from the nail bed, when a positioning pin at a specific location malfunctions, the positioning mechanism containing that pin can be disassembled for repair or replacement.

[0050] It should be noted that there are multiple ways to implement a positioning pin with raised and lowered states; this embodiment provides the following implementation. Please refer to [link / reference]. Figure 8The first positioning pin and the second positioning pin each include a sleeve and a shaft, with the sleeve fitted onto the shaft. The shaft of the first positioning pin can move relative to the sleeve of the first positioning pin under the push of a first actuating element. The shaft of the second positioning pin can move relative to the sleeve of the second positioning pin under the push of a second actuating element. A protruding post is formed radially extending from the side of the shaft. A locking hole is formed in the sleeve, and the protruding post passes through the locking hole. The locking hole includes a plurality of first locking portions, a plurality of second locking portions, and a guide portion. The plurality of first locking portions and the plurality of second locking portions are alternately arranged along the circumference of the sleeve. The guide portion is used to guide the protruding post to move from the first locking portion to the adjacent second locking portion, or to guide the protruding post to move from the second locking portion to the adjacent first locking portion. In this implementation, the guide part guides the protrusion to move in the manner described above, so that after the shaft moves relative to the sleeve, the positioning pin is in the raised state when the protrusion is in the first locking part, and in the lowered state when the protrusion is in the second locking part; or, the positioning pin is in the lowered state when the protrusion is in the first locking part, and in the raised state when the protrusion is in the second locking part.

[0051] Furthermore, the locking hole can be implemented in various ways; this embodiment provides the following implementation method. Please refer to [link / reference]. Figure 8 The sleeve has multiple first teeth and multiple second teeth, with the first teeth protruding upwards and the second teeth protruding downwards. A locking hole is formed between the first and second teeth. The first teeth face the groove between adjacent second teeth. The groove between adjacent first teeth forms a first locking portion or a second locking portion. The sidewall of the groove between adjacent second teeth and / or the sidewall of the first teeth at least partially forms a guide portion. In this implementation, the bottom end of the second locking portion can be lower than the bottom end of the first locking portion, so that when the shaft moves relative to the sleeve, the positioning pin is in a raised state when the protrusion is in the first locking portion and in a lowered state when the protrusion is in the second locking portion. The first teeth face the groove between adjacent second teeth, so that the multiple first teeth and multiple second teeth are staggered, and when the shaft is pushed upwards, the protrusion can move along the sidewall of the groove between adjacent second teeth and / or the sidewall of the first teeth, and then move into the adjacent locking portion.

[0052] Furthermore, the second locking part can be implemented in various ways; this embodiment provides the following implementation. Please refer to [link / reference]. Figure 8 The second locking part includes a downwardly extending sub-groove. In this implementation, when the protrusion moves from the first locking part to the second locking part, the protrusion falls into the downwardly extending sub-groove, thereby changing the positioning pin from a raised state to a lowered state.

[0053] In summary, the nail bed provided in this application includes a table, a first positioning pin, a second positioning pin, a lifting mechanism, and a drive assembly. The lifting mechanism includes a first lifting component and a second lifting component that are not co-located. A first actuating element of the first lifting component can push the first positioning pin upward, and a second actuating element of the second lifting component can push the second positioning pin upward. The drive assembly drives the first lifting component and the second lifting component to move between the front and rear ends of the table. This solves the problem of providing a stable and rapid lifting mechanism for a nail bed with high-density pins.

[0054] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A nail bed, characterized in that, include: The tabletop is provided with a plurality of first pinholes and a plurality of second pinholes, the first pinholes and the second pinholes being distributed in columns and rows, with the first pinholes located in odd-numbered columns and the second pinholes located in even-numbered columns; The first positioning pin is positioned at the first pinhole; The second positioning pin is disposed in the second pin hole; both the first positioning pin and the second positioning pin have a raised state and a lowered state. A lifting mechanism includes a first lifting component and a second lifting component that are not arranged in a row; the first lifting component includes a plurality of first actuators arranged in a row, the first actuators being located below the first positioning pin, for pushing the first positioning pin upward to switch the first positioning pin between a raised state and a lowered state; the second lifting component includes a plurality of second actuators arranged in a row; the second actuators being located below the second positioning pin, for pushing the second positioning pin upward to switch the second positioning pin between a raised state and a lowered state; A drive assembly is used to drive the first lifting assembly and the second lifting assembly to move between the opposite front and rear ends of the platform, so that the first positioning pin can be pushed upward by the first actuating member and the second positioning pin can be pushed upward by the second actuating member.

2. The nail bed as described in claim 1, characterized in that, The nail bed also includes multiple detection elements; the detection elements are used to detect the state of the first positioning pin or the second positioning pin from below; The testing component can move between the front and rear ends of the platform.

3. The nail bed as described in claim 2, characterized in that, The lifting mechanism further includes a mounting component, wherein the first lifting assembly, the second lifting assembly, and the detection component are disposed on the mounting component; The drive assembly includes a first slide rail and a drive member, and the mounting member is disposed on the first slide rail; the drive member is used to drive the mounting member to move between the opposite front and rear ends of the table surface.

4. The nail bed as described in claim 2, characterized in that, The detection element includes a distance sensor, which is used to detect the distance between itself and the lower end of the first positioning pin or the lower end of the second positioning pin.

5. The nail bed as described in any one of claims 2-4, characterized in that, Multiple of the aforementioned testing components are arranged in a row.

6. The nail bed as described in claim 1, characterized in that, The number of the first lifting components is multiple, and they are parallel to each other.

7. The nail bed as described in claim 6, characterized in that, Multiple sets of the first lifting components can move from the front end to the rear end of the platform, or multiple sets of the first lifting components can move from the rear end to the front end of the platform.

8. The nail bed as described in claim 6, characterized in that, The number of the first lifting components is two sets. One set of the first lifting components can move from the front end of the table to the middle of the table, and the other set of the first lifting components can move from the rear end of the table to the middle of the table.

9. The nail bed as described in any one of claims 6-8, characterized in that, Multiple sets of the first lifting components can move synchronously.

10. The nail bed as described in claim 1, characterized in that, The platform is covered with a protective component, which has a third pinhole for at least part of the first or second positioning pin to pass through; the protective component is a magnetic component. The tabletop is provided with a magnet, or a magnet is provided near the tabletop, and the protective component is attracted to the tabletop by the magnet.

11. The nail bed as described in claim 10, characterized in that, The protective components are configured in multiple ways, and the multiple protective components are laid and spliced ​​on the table surface.

12. The nail bed as described in claim 1, characterized in that, The nail bed also includes multiple positioning mechanisms, each positioning mechanism including a fixed base, a first positioning pin and / or a second positioning pin, wherein the first positioning pin and / or the second positioning pin are disposed on the fixed base; Multiple positioning mechanisms are detachably assembled and laid on the nail bed.

13. The nail bed as described in claim 1, characterized in that, The first positioning pin and the second positioning pin each include a sleeve and a shaft body, with the sleeve sleeved on the shaft body; The shaft of the first positioning pin can move relative to the sleeve of the first positioning pin under the push of the first actuating member; the shaft of the second positioning pin can move relative to the sleeve of the second positioning pin under the push of the second actuating member; A protruding post is formed radially on the side of the shaft body, and a locking hole is formed on the sleeve. The protruding post passes through the locking hole. The locking hole includes a plurality of first locking parts, a plurality of second locking parts, and a guide part. The plurality of first locking parts and the plurality of second locking parts are alternately arranged along the circumference of the sleeve. The guide part is used to guide the protruding post to move from the first locking part to the adjacent second locking part, or to guide the protruding post to move from the second locking part to the adjacent first locking part.

14. The nail bed as described in claim 13, characterized in that, The sleeve has a plurality of first teeth and a plurality of second teeth, the first teeth protruding upwards and the second teeth protruding downwards; the locking hole is formed between the first teeth and the second teeth. The first tooth faces the groove between the adjacent second teeth; The groove between adjacent first teeth forms the first locking portion or the second locking portion; the sidewall of the groove between adjacent second teeth and / or the sidewall of the first tooth at least partially forms the guide portion.

15. The nail bed as described in claim 14, characterized in that, The second locking part includes a downwardly extending sub-groove.

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