Welding positioning tool for multilayer structure of integrated circuit

Abstract

The invention relates to the technical field of integrated circuit board welding, and discloses an integrated circuit multilayer structure welding positioning tool which comprises a base and an alignment extrusion positioning assembly, the top of the base is fixedly connected with an annular shell, the bottom of the base is provided with a negative pressure shell, and the top of the negative pressure shell penetrates to the top of the base and is provided with an air draft hole; the aligning, extruding and positioning assembly comprises two wedge-shaped blocks, the opposite sides of the two wedge-shaped blocks penetrate to the outer side of the annular shell, and pressing rollers are arranged at the tops of the wedge-shaped blocks. The lower layer structure of the integrated circuit is fixed through adsorption force generated by the negative pressure shell and the air draft hole, sliding of the lower layer structure is prevented, the negative pressure mechanism is used for adjusting air pressure in the pressure pipe, the piston plate is driven to drive the mounting rod to control the pressing roller to move downwards, and the pressing roller makes contact with and pushes the wedge-shaped block to laterally stretch out of the annular shell to conduct synchronous extrusion positioning on the upper layer structure. The process is automatically triggered by air pressure change, it is ensured that force applied to each layer of structure by the wedge-shaped block is uniform and consistent, and deviation caused by manual operation is avoided.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit board welding technology, and in particular to welding positioning fixtures for multilayer integrated circuit structures. Background Technology

[0002] Integrated circuit welding refers to the technical process of connecting integrated circuit chips to circuit boards or other substrates through welding technology. Its core is to achieve electrical connection and mechanical fixation between the chip and the substrate through solder. Welding methods include reflow soldering, wave soldering, laser soldering, etc. Welding quality directly affects the electrical performance, heat dissipation capacity and long-term stability of integrated circuits, and is a key link in electronic manufacturing. In the welding process of multi-layer integrated circuit structures, positioning fixtures are required.

[0003] Chinese patent application CN220217012U discloses a welding positioning fixture for integrated circuit boards, including a substrate, a positioning clamping assembly at the upper end of the substrate, a base at the lower end of the substrate, a circuit board adjustment assembly between the substrate and the base, a soldering iron holder on one side of the upper end of the base, and a soldering iron above the soldering iron holder. This invention, by setting up the positioning clamping assembly, achieves convenient manual positioning of the integrated circuit board, avoiding the high positioning cost associated with using multiple cylinders and motors for positioning the integrated circuit board, thus reducing the positioning cost of the integrated circuit board. By setting up the circuit board adjustment assembly, it enables convenient adjustment of the welding position of the integrated circuit board, avoiding the inconvenience for workers to weld at different positions on the integrated circuit board and the low practicality of the fixture, thereby improving the practicality of the fixture.

[0004] Although this patent can quickly fix the circuit board through the positioning clamping component, and does not require multiple cylinders and motors, reducing positioning costs and allowing for convenient adjustment of the circuit board's soldering position, thus improving its practicality, when soldering multi-layer integrated circuit structures, it is difficult to ensure the accuracy and consistency of contact between the pressure plate and each layer by manually adjusting the position of the pressure plate. During the downward positioning, the lower layer of the integrated circuit is prone to shift, affecting its soldering accuracy and making it unsuitable for use. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above-mentioned integrated circuit board welding positioning fixtures, this invention is proposed.

[0007] Therefore, the problem that this invention aims to solve is that when existing integrated circuit board welding positioning fixtures are used to position the multi-layer structure of integrated circuit boards, the manual control of the pressure plate to press down easily causes the upper and lower layers to shift, affecting the welding accuracy.

[0008] To solve the above technical problems, the present invention provides the following technical solution: a multilayer structure welding positioning fixture for integrated circuits, comprising a base and an alignment and extrusion positioning assembly. An annular shell is fixedly connected to the top of the base, and a negative pressure shell is provided at the bottom of the base. The top of the negative pressure shell extends through to the top of the base and has an exhaust hole. The alignment and extrusion positioning assembly includes two wedge-shaped blocks, with one side of each wedge extending through to the outer side of the annular shell. A pressure roller is provided on the top of each wedge-shaped block. Adjusting tubes are fixedly connected to the front and rear sides of both sides of the inner cavity of the base. A piston plate is provided within the inner cavity of the adjusting tube, and an mounting rod is fixedly connected to the top of the piston plate. The top of the mounting rod extends through to the inner cavity of the annular shell and is movably connected to the pressure roller. A negative pressure mechanism is provided on the rear side of the top of the inner cavity of the base. The front side of the negative pressure mechanism communicates with the negative pressure shell, and both sides of the negative pressure shell communicate with the adjusting tube.

[0009] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, the negative pressure mechanism includes a pressure tube. The top of the pressure tube is fixedly connected to the inner wall of the base. A screw is movably connected to the right side of the inner cavity of the pressure tube. A sealing plate is threadedly connected to the surface of the screw. The left side of the screw extends through to the outside of the base and is fixedly connected to a knob. The pressure tube facilitates the installation of the screw. The screw can be adjusted in position inside the pressure tube through the threaded engagement with the sealing plate. During the movement of the sealing plate, the air inside the negative pressure shell and the adjusting tube can be extracted, so that the adjusting tube and the negative pressure shell are in a negative pressure state, thereby improving the stable clamping and positioning of the multilayer integrated circuit board.

[0010] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, the top and bottom of the sealing plate are provided with sliding grooves, and the inner cavity of the sliding grooves is slidably connected with slide rails. The opposite sides of the two slide rails are fixedly connected to the pressure tube. The right side of the screw is movably connected to the inner wall of the pressure tube through a bearing. The sliding grooves and slide rails are used to limit the sealing plate and prevent the screw from controlling the rotation of the sealing plate, so that the sealing plate can be smoothly adjusted to the left and right positions.

[0011] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, a push plate is fixedly connected to the side of the wedge block away from the pressure roller, and a spring is fixedly connected to the bottom of the piston plate. The push plate can increase the squeezing range of the wedge block on the integrated circuit board and improve the positioning effect, and the spring can make the piston plate quickly reset.

[0012] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, both sides of the negative pressure shell are connected to the regulating tube through a T-tube, and the top of the base is provided with a mounting hole for use with the negative pressure shell. The T-tube facilitates the rapid flow of air inside the regulating tube into the negative pressure shell, and the mounting hole facilitates the installation and fixing of the negative pressure shell.

[0013] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, the inner wall of the annular shell is provided with a movable opening for use with the wedge block, and the inner cavity of the negative pressure shell is provided with an airtight movable plate, wherein: the movable opening enables the wedge block to move smoothly left and right, and the airtight movable plate can improve the adsorption effect of the negative pressure shell on the integrated circuit board.

[0014] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, a pressing mechanism is provided on the front side of the top of the base. The pressing mechanism includes a threaded post, the rear side of which is fixedly connected to the base. A telescopic sleeve is threadedly connected to the surface of the threaded post. The front side of the telescopic sleeve passes through the base and is movably connected to a mounting bracket. A movable shell is fixedly connected to the top of the mounting bracket. An elastic sheet is fixedly connected to the inner wall of the movable shell. A pressing block is fixedly connected to the rear side of the elastic sheet. The threaded post can cooperate with the telescopic sleeve to control the position of the mounting bracket and the movable shell, push the movable shell towards the integrated circuit board, so that the pressing block can hold the integrated circuit board, increasing its positioning stability. After welding is completed, the movable shell is controlled to reset, making it easy to remove the integrated circuit board.

[0015] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, the rear side of the threaded column is fixedly connected to the base by a mounting block, and the front side of the telescopic sleeve is fixedly connected to a turntable. The surface of the turntable is provided with anti-slip texture. The mounting block is used to increase the stability of the threaded column installation and fixing, the turntable makes it easy for the user to rotate the telescopic sleeve, and the anti-slip texture can improve the anti-slip effect of the turntable.

[0016] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, the inner wall of the mounting bracket and the telescopic sleeve are movably connected by a bearing. The inner wall of the telescopic sleeve is provided with a thread for use with a threaded post. The bearing can be used without affecting the position of the adjustable movable shell of the mounting bracket when the telescopic sleeve rotates, and the thread inside the telescopic sleeve can cooperate with the threaded post to control the movement of the mounting bracket.

[0017] As a preferred embodiment of the integrated circuit multilayer structure welding positioning fixture of the present invention, limit grooves are provided on both sides of the bottom of the movable shell, and limit strips are slidably connected to the inner wall of the limit grooves. The bottom of the limit strips is fixedly connected to the base. The limit grooves and limit strips are used to improve the stability of the movable shell during movement.

[0018] The beneficial effects of this invention are as follows: the suction force generated by the negative pressure shell and the exhaust hole fixes the lower layer structure of the integrated circuit and prevents it from sliding. The negative pressure mechanism adjusts the internal air pressure of the pressure tube, drives the piston plate to drive the mounting rod to control the pressure roller to move down. The pressure roller contacts and pushes the wedge block to extend from the side of the annular shell, and performs synchronous extrusion and positioning on the upper layer structure. This process is automatically triggered by changes in air pressure, ensuring that the wedge block applies uniform force to each layer structure and avoids deviation caused by manual operation. Combined with the threaded column and telescopic sleeve in the extrusion mechanism to adjust the position of the movable shell, the elastic plate pushes the extrusion block to provide auxiliary fixation, ensuring the accurate and stable position of the multi-layer integrated circuit board during the welding process. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments 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 these drawings without creative effort. Wherein: Figure 1 A structural diagram of a welding positioning fixture for multilayer integrated circuit structures; Figure 2 A bottom view of a welding positioning fixture for multilayer integrated circuit structures; Figure 3 A cross-sectional view of the annular shell of a welding positioning fixture for multilayer integrated circuit structures; Figure 4 Cross-sectional view of the negative pressure shell and regulating tube of the welding positioning fixture for multilayer structures of integrated circuits; Figure 5 Cross-sectional view of the pressure tube of a welding positioning fixture for multilayer integrated circuit structures; Figure 6 Exploded view of the extrusion mechanism for a welding positioning fixture for multilayer integrated circuit structures. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments. Example 1

[0023] Reference Figures 1-5 This is the first embodiment of the present invention, which provides a multilayer welding positioning fixture for integrated circuits. The multilayer welding positioning fixture for integrated circuits includes a base 1 and an alignment and compression positioning assembly 5. An annular shell 2 is fixedly connected to the top of the base 1, and a negative pressure shell 3 is provided at the bottom of the base 1. The top of the negative pressure shell 3 extends through to the top of the base 1 and has an exhaust hole 4. The alignment and compression positioning assembly 5 includes two wedge blocks 51, with one side of each wedge block 51 extending through to the outside of the annular shell 2. A pressure roller 52 is provided at the top of each wedge block 51. Adjusting tubes 53 are fixedly connected to the front and rear sides of both sides of the inner cavity of the base 1. A piston plate 54 is provided in the inner cavity of the adjusting tube 53. A mounting rod 55 is fixedly connected to the top of the base 1. The top of the mounting rod 55 extends through the inner cavity of the annular shell 2 and is movably connected to the pressure roller 52. A negative pressure mechanism 56 is provided on the rear side of the top of the inner cavity of the base 1. The front side of the negative pressure mechanism 56 is connected to the negative pressure shell 3. Both sides of the negative pressure shell 3 are connected to the adjusting pipe 53. A push plate is fixedly connected to the side of the wedge block 51 away from the pressure roller 52. A spring 57 is fixedly connected to the bottom of the piston plate 54. Both sides of the negative pressure shell 3 are connected to the adjusting pipe 53 through a three-way pipe. The top of the base 1 is provided with a mounting hole that cooperates with the negative pressure shell 3. The inner wall of the annular shell 2 is provided with a movable opening that cooperates with the wedge block 51. An airtight movable plate 58 is provided in the inner cavity of the negative pressure shell 3.

[0024] Specifically, the annular shell 2 can limit the position of the integrated circuit board, allowing it to be stably placed on top of the base 1. The negative pressure shell 3 can extract air, and the exhaust hole 4 on its top can also extract air, allowing the integrated circuit board to be tightly adsorbed on top of the base 1. The negative pressure mechanism 56 can extract air from the inside of the negative pressure shell 3 and the regulating tube 53. The piston plate 54 inside the regulating tube 53 moves downward under the influence of air pressure, causing the piston plate 54 to cooperate with the mounting rod 55 to control the movement of the pressure roller 52. The pressure roller 52 squeezes the slope of the wedge block 51, causing it to move out of the annular shell 2 and squeeze the multi-layer integrated circuit board, ensuring that each layer is precisely aligned, thus avoiding the impact of the upper and lower circuit boards' positional misalignment on the soldering accuracy during reflow soldering.

[0025] Specifically, the push plate can increase the squeezing range of the wedge block 51 on the integrated circuit board and improve the positioning effect; the spring 57 can make the piston plate 54 quickly reset; the three-way pipe facilitates the rapid flow of air inside the regulating pipe 53 into the negative pressure shell 3; the mounting hole facilitates the installation and fixation of the negative pressure shell 3; the movable opening can make the wedge block 51 move smoothly left and right; and the airtight movable plate 58 can improve the adsorption effect of the negative pressure shell 3 on the integrated circuit board. Example 2

[0026] Reference Figure 2 and Figure 5 This is the second embodiment of the present invention. Based on the previous embodiment, the negative pressure mechanism 56 includes a pressure tube 561. The top of the pressure tube 561 is fixedly connected to the inner wall of the base 1. A screw 562 is movably connected to the right side of the inner cavity of the pressure tube 561. A sealing plate 563 is threadedly connected to the surface of the screw 562. A knob is fixedly connected to the left side of the screw 562 through to the outside of the base 1. Slide grooves are provided at the top and bottom of the sealing plate 563. Slide rails are slidably connected to the inner cavity of the slide grooves. The opposite sides of the two slide rails are fixedly connected to the pressure tube 561. The right side of the screw 562 is movably connected to the inner wall of the pressure tube 561 through a bearing.

[0027] Specifically, the pressure tube 561 facilitates the installation of the screw 562. The screw 562 can be adjusted in position inside the pressure tube 561 through the threaded engagement with the sealing plate 563. During the movement of the sealing plate 563, the air inside the negative pressure shell 3 and the regulating tube 53 can be extracted, so that the regulating tube 53 and the negative pressure shell 3 are in a negative pressure state, thereby improving the stable clamping and positioning of the multilayer integrated circuit board.

[0028] Specifically, the groove and slide rail are used to limit the position of the sealing plate 563, preventing the screw 562 from controlling the rotation of the sealing plate 563, so that the sealing plate 563 can be smoothly adjusted in the left and right positions. Example 3

[0029] Reference Figure 1 , Figure 2 and Figure 6This is the third embodiment of the present invention, which is based on the first two embodiments. A pressing mechanism 6 is provided on the front side of the top of the base 1. The pressing mechanism 6 includes a threaded post 61. The rear side of the threaded post 61 is fixedly connected to the base 1. A telescopic sleeve 62 is threadedly connected to the surface of the threaded post 61. The front side of the telescopic sleeve 62 passes through the base 1 and is movably connected to a mounting bracket 63. A movable shell 64 is fixedly connected to the top of the mounting bracket 63. An elastic sheet 65 is fixedly connected to the inner wall of the movable shell 64. A pressing block 66 is fixedly connected to the rear side of the elastic sheet 65. The rear side of the threaded post 61 is fixedly connected to the base 1 through the mounting block. A turntable is fixedly connected to the front side of the telescopic sleeve 62. The surface of the turntable is provided with anti-slip texture. The inner wall of the mounting bracket 63 is movably connected to the telescopic sleeve 62 through a bearing. The inner wall of the telescopic sleeve 62 is provided with a thread that cooperates with the threaded post 61. Limit grooves are provided on both sides of the bottom of the movable shell 64. Limit strips are slidably connected to the inner wall of the limit grooves. The bottom of the limit strips is fixedly connected to the base 1.

[0030] Specifically, the threaded column 61 can cooperate with the telescopic sleeve 62 to control the position of the mounting bracket 63 and the movable shell 64, push the movable shell 64 towards the integrated circuit board, so that the pressing block 66 can hold the integrated circuit board, increasing its positioning stability. After the welding is completed, the movable shell 64 is controlled to reset, making it easy to remove the integrated circuit board.

[0031] Specifically, the mounting block is used to increase the stability of the threaded post 61, the turntable makes it easy for the user to rotate the telescopic sleeve 62, and the anti-slip texture can improve the anti-slip effect of the turntable.

[0032] Specifically, the bearing can rotate without affecting the position of the movable housing 64 of the mounting bracket 63, and the internal thread of the telescopic sleeve 62 can cooperate with the threaded post 61 to control the movement of the mounting bracket 63.

[0033] Specifically, the limiting groove and limiting strip are used to improve the stability of the moving shell 64 during movement.

[0034] In use, the multi-layer integrated circuit is placed on top of the base 1, and the annular shell 2 limits its position to ensure initial alignment. Rotating the screw 562 moves the sealing plate 563 within the pressure tube 561 to extract air. The air inside the negative pressure shell 3 and the regulating tube 53 is extracted, causing the negative pressure shell 3 to generate suction force through the exhaust hole 4, firmly fixing the lower structure and preventing it from sliding during the welding process. At the same time, the piston plate 54 inside the regulating tube 53 moves down to compress the spring 57. When the piston plate 54 moves, it controls the mounting rod 55 and the pressure roller 52 to move down. Through the pressure roller 52 squeezing the slope of the wedge block 51, it moves out of the annular shell 2 to support the multi-layer integrated circuit. The integrated circuits in the multi-layer structure are uniformly extruded to ensure precise alignment of the multi-layer structure and prevent misalignment. Then, the turntable is rotated, causing the telescopic sleeve 62 to rotate and move on the threaded post 61, pushing the mounting bracket 63 and the movable shell 64 to slide. When the extrusion block 66 contacts the integrated circuit, the elastic sheet 65 is compressed, causing the extrusion block 66 to press against the side of the integrated circuit, providing additional fixing force and enhancing overall stability. The wedge block 51 is used to clamp and position the upper integrated circuit, while the negative pressure shell 3 and the exhaust hole 4 are used to fix the lower integrated circuit. The force applied to each layer is uniform and consistent, avoiding misalignment caused by manual operation and improving welding accuracy.

[0035] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An integrated circuit multilayer structure soldering positioning tool, characterized by: Including base (1) and alignment extrusion positioning assembly (5), the top of the base (1) is fixedly connected with the annular shell (2), the bottom of the base (1) is provided with negative pressure shell (3), the top of the negative pressure shell (3) penetrates to the top of the base (1) and is provided with a suction hole (4); The alignment extrusion positioning assembly (5) includes two wedge blocks (51), the opposite sides of the two wedge blocks (51) penetrate to the outside of the annular shell (2), the top of the wedge block (51) is provided with a compression roller (52), the front and rear sides of the two sides of the inner cavity of the base (1) are fixedly connected with adjusting pipes (53), the inner cavity of the adjusting pipe (53) is provided with a piston plate (54), the top of the piston plate (54) is fixedly connected with a mounting rod (55), the top of the mounting rod (55) penetrates to the inner cavity of the annular shell (2) and is movably connected with the compression roller (52), the rear side of the top of the inner cavity of the base (1) is provided with a negative pressure mechanism (56), the front side of the negative pressure mechanism (56) is communicated with the negative pressure shell (3), and the two sides of the negative pressure shell (3) are communicated with the adjusting pipes (53).

2. The integrated circuit multilayer structure soldering positioning fixture of claim 1, wherein: The negative pressure mechanism (56) includes a pressure pipe (561), the top of the pressure pipe (561) is fixedly connected with the inner wall of the base (1), the right side of the inner cavity of the pressure pipe (561) is movably connected with a screw rod (562), the surface of the screw rod (562) is threadedly connected with a sealing plate (563), and the left side of the screw rod (562) penetrates to the outside of the base (1) and is fixedly connected with a knob.

3. The integrated circuit multilayer structure bonding fixture of claim 2, wherein: The top and bottom of the sealing plate (563) are provided with a sliding groove, the inner cavity of the sliding groove is slidably connected with a sliding rail, and the opposite sides of the two sliding rails are fixedly connected with the pressure pipe (561).

4. The integrated circuit multilayer structure soldering positioning tooling fixture of claim 1, wherein: The right side of the screw rod (562) is movably connected with the inner wall of the pressure pipe (561) through a bearing.

5. The integrated circuit multilayer structure soldering positioning fixture of claim 1, wherein: The side of the wedge block (51) away from the compression roller (52) is fixedly connected with a push plate, and the bottom of the piston plate (54) is fixedly connected with a spring (57).

6. The integrated circuit multilayer structure soldering positioning fixture of claim 1, wherein: The two sides of the negative pressure shell (3) are communicated with the adjusting pipes (53) through three-way pipes, and the top of the base (1) is provided with a mounting hole matched with the negative pressure shell (3).

7. The integrated circuit multilayer structure bonding fixture of claim 1, wherein: The inner wall of the annular shell (2) is provided with a movable opening matched with the wedge block (51), and the inner cavity of the negative pressure shell (3) is provided with an airtight movable plate (58). The front side of the top of the base (1) is provided with an extrusion mechanism (6), the extrusion mechanism (6) includes a threaded column (61), the rear side of the threaded column (61) is fixedly connected with the base (1), the surface of the threaded column (61) is threadedly connected with an expansion sleeve (62), the front side of the expansion sleeve (62) penetrates the base (1) and is movably connected with a mounting frame (63), the top of the mounting frame (63) is fixedly connected with a movable shell (64), the inner wall of the movable shell (64) is fixedly connected with an elastic sheet (65), and the rear side of the elastic sheet (65) is fixedly connected with an extrusion block (66).

8. The integrated circuit multilayer structure bonding fixture of claim 7, wherein: The rear side of the threaded column (61) is fixedly connected with the base (1) through a mounting block, and the front side of the telescopic sleeve (62) is fixedly connected with a rotating disc, and the surface of the rotating disc is provided with anti-skid lines.

9. The integrated circuit multilayer structure bonding fixture of claim 7, wherein: The inner wall of the mounting rack (63) is movably connected with the telescopic sleeve (62) through a bearing, and the inner wall of the telescopic sleeve (62) is provided with threads matched with the threaded column (61).

10. The integrated circuit multilayer structure bonding fixture of claim 7, wherein: The two sides of the bottom of the movable shell (64) are both provided with limiting grooves, the inner wall of the limiting groove is slidably connected with a limiting strip, and the bottom of the limiting strip is fixedly connected with the base (1).

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