Press fit type HDI circuit board

Abstract

The utility model discloses a press fit type HDI circuit board, which comprises a circuit board, one side of the circuit board is provided with a bottom plate, the bottom plate is provided with a fast installation device, the fast installation device comprises a pressing rod, an installation hole, a fixing sleeve, a clamping groove, a clamping block, a storage groove and a spring, the installation hole is arranged on the circuit board, the fixing sleeve is fixedly arranged on the bottom plate, the clamping groove is arranged on the inner side of the fixing sleeve, and the clamping block is arranged on the inner side of the clamping sleeve. The storage groove is formed in the inner side of the pressing rod, one side of the clamping block is connected with the inner wall of the extrusion groove through a spring, a quick release mechanism is arranged on the outer side of the pressing rod and comprises a push spring, a push plate, a clamping sleeve, an extrusion groove, a movable plate and a movable spring, the other end of the push spring is connected with the top end of the push plate, the other end of the movable spring is connected with the movable plate, and the movable plate is fixedly connected with the clamping sleeve. According to the quick-mounting and quick-dismounting device, quick mounting can be achieved, safe dismounting is facilitated, and the quick-mounting and quick-dismounting device has important practical significance in improving production efficiency, reducing maintenance cost and promoting sustainability of products.

Description

Technical Field

[0001] This utility model relates to the field of laminated HDI circuit board technology, and more specifically, it relates to a laminated HDI circuit board. Background Technology

[0002] In the field of modern electronic product manufacturing, laminated HDI (High Density Interconnect) circuit boards are widely used due to their high-density interconnection characteristics. However, current technology still has significant shortcomings in the installation and removal of circuit boards, which not only affects production efficiency but may also lead to product quality and reliability issues.

[0003] First, existing circuit board installation methods are generally cumbersome. Traditional installation methods usually require the use of specialized tools such as screwdrivers. This method is not only time-consuming but also increases the complexity of the operation. In large-scale production environments, this cumbersome installation process will significantly reduce production efficiency and increase labor costs. In addition, the use of tools for installation may also damage the circuit board due to improper operation. For example, over-tightening of screws may cause the circuit board to deform or the circuit to be damaged. This not only increases the scrap rate of products but may also affect the quality and reliability of the final product.

[0004] Secondly, while some improved designs achieve rapid circuit board installation through special structures, these designs often neglect the ease of disassembly. This one-dimensional design approach leads to new problems. During product repair, upgrades, or recycling, quick and safe disassembly of circuit boards becomes crucial. However, existing quick-installation designs typically fail to consider this, resulting in disassembly still requiring specialized tools, making the process complex and time-consuming. More seriously, some designs may cause irreversible damage to the circuit board or base plate during disassembly. For example, some snap-fit ​​designs, while convenient for installation, may require excessive force during disassembly, leading to snap breakage or circuit board bending and deformation. Difficult disassembly not only increases the cost of maintenance and replacement but may also lead to more serious problems. In some cases, operators may resort to violent disassembly, which can damage not only the circuit board and the base plate but also other electronic components. This practice not only violates the original design intent of electronic products but may also create safety hazards, such as fragments of electronic components that could injure operators. Furthermore, the difficult-to-disassemble design hinders the sustainable development of electronic products. In today's context of increasing environmental awareness, the recyclability and repairability of electronic products are becoming increasingly important. If circuit boards cannot be easily disassembled, it will greatly increase the difficulty of product recycling and parts reuse, which contradicts the concept of a circular economy. Utility Model Content

[0005] (a) Technical problems to be solved

[0006] In view of the problems existing in the prior art, this utility model provides a press-fit HDI circuit board to solve the technical problems mentioned in the background art.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, this utility model provides the following technical solution: a press-fit HDI circuit board, comprising a circuit board, a base plate on one side of the circuit board, a quick-release device mounted on the base plate, the quick-release device comprising a pressing rod, a mounting hole, a fixing sleeve, a slot, a locking block, a storage groove, and a spring, the mounting hole being formed on the circuit board, the fixing sleeve being fixedly mounted on the base plate, the slot being formed inside the fixing sleeve, the storage groove being formed inside the pressing rod, and the locking block being connected to the pressing groove on one side by a spring. The pressing rod is connected to the wall, and a quick-release mechanism is provided on the outside of the pressing rod. The quick-release mechanism includes a push spring, a push plate, a sleeve, a squeezing groove, a movable plate, and a movable spring. One end of the push spring is connected to the bottom end of the sleeve, and the other end of the push spring is connected to the top end of the push plate. One side of the push plate is in contact with the inner side of the base plate. One end of the movable spring is connected to the bottom end of the pressing rod, and the other end of the movable spring is connected to the movable plate. The movable plate is fixedly connected to the sleeve. The sleeve is fitted on the outside of the pressing rod, and the squeezing groove is formed on the side wall of the sleeve.

[0009] The present invention is further configured such that the quick-installation device, the quick-release mechanism, and the mounting holes are provided at least four times, and the mounting holes are designed with an asymmetrical structure.

[0010] The present invention is further provided that a card plate is fixedly provided at the top of the card sleeve.

[0011] The present invention is further configured such that the inner walls of the card slot and the extrusion groove are both designed with chamfered structure, and the lower side of the card block is chamfered.

[0012] The present invention is further configured such that the bottom end of the push plate adopts a chamfered structure design and the top end of the pressing rod adopts a rounded corner treatment.

[0013] The present invention is further configured such that a slide rail is fixedly provided on the inner wall of the sleeve, and a corresponding slide groove is provided on the outer side of the pressing rod. The slide groove is adapted to the slide rail. The arrangement of the slide rail and the slide groove increases the contact surface, improves the friction of the pressing rod sliding, and makes sliding more laborious.

[0014] The present invention is further configured such that a plurality of balls are rolled on the outer side of the sleeve, and a guide groove is provided on the inner side of the fixing sleeve, and the balls roll in the guide groove. The above components ensure the smooth sliding of the sleeve and reduce the sliding friction of the sleeve.

[0015] The present invention is further configured such that the diameter of the push spring is greater than the diameter of the movable spring, and the number of turns of the push spring is greater than the number of turns of the movable spring. The above structural design ensures that the restoring force of the push spring is greater than the restoring force of the movable spring.

[0016] (III) Beneficial Effects

[0017] Compared with the prior art, this utility model provides a laminated HDI circuit board with the following features:

[0018] Beneficial effects:

[0019] 1. The quick-installation device, through its cleverly designed pressing rod, fixing sleeve, slot, locking block, and spring structure, enables rapid installation of circuit boards. Operators only need to align the mounting holes on the circuit board with the fixing sleeve on the base plate and press the pressing rod to complete the installation. No special tools such as screwdrivers are required, which greatly simplifies the installation process, improves production efficiency, and reduces labor costs. At the same time, this design avoids damage to the circuit board that may be caused by improper tool operation, such as deformation or circuit damage caused by over-tightening screws, thereby improving product quality and reliability and reducing the scrap rate.

[0020] 2. The quick-release mechanism design solves the problem of difficult disassembly in existing technologies. Through the ingenious cooperation of push springs, push plates, ferrules, compression grooves, movable plates, and movable springs, the circuit board can be quickly disassembled. Operators only need to press the push rod and then gently pull out the ferrule to complete the disassembly. The entire process requires no tools and is simple and quick to operate. This design not only greatly improves the efficiency of maintenance and upgrades but also avoids the violent disassembly methods that may be used due to difficult disassembly, effectively preventing damage to the circuit board, base plate, and other electronic components. At the same time, the quick-release mechanism design takes into account the balance of forces and the protection of components, such as the reasonable configuration of push springs and movable springs, as well as the use of ball bearings and guide grooves, to ensure the smoothness and safety of the disassembly process and reduce operational risks. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of a lamination-type HDI circuit board according to the present invention;

[0022] Figure 2 This is a cross-sectional structural diagram of the quick-installation device and quick-release mechanism in this utility model;

[0023] Figure 3 This is a cross-sectional view of the quick-installation device and quick-release mechanism in this utility model from a second angle.

[0024] Figure 4 This is a schematic diagram of the structure of the ferrule and the pressing rod in this utility model;

[0025] Figure 5This is a cross-sectional view of the ferrule and the pressing rod in this utility model.

[0026] In the diagram: 1. Circuit board; 2. Base plate; 3. Pressing rod; 4. Mounting hole; 5. Fixing sleeve; 6. Slot; 7. Locking block; 8. Storage slot; 9. Spring; 10. Push spring; 11. Push plate; 12. Sleeve; 13. Extrusion groove; 14. Movable plate; 15. Movable spring; 16. Locking plate; 17. Slide rail; 18. Slide groove; 19. Ball bearing; 20. Guide groove. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] In this utility model, unless otherwise stated, the orientations used, such as "up" and "down", usually refer to the direction shown in the accompanying drawings, or to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" usually refer to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0030] Please see Figures 1-5 A press-fit HDI circuit board includes a circuit board 1, a base plate 2 on one side of the circuit board 1, and a quick-release device mounted on the base plate 2. The quick-release device includes a pressing rod 3, a mounting hole 4, a fixing sleeve 5, a slot 6, a locking block 7, a storage groove 8, and a spring 9. The mounting hole 4 is formed on the circuit board 1, the fixing sleeve 5 is fixedly mounted on the base plate 2, the slot 6 is formed inside the fixing sleeve 5, the storage groove 8 is formed inside the pressing rod 3, and one side of the locking block 7 is connected to the inner wall of the pressing groove 13 via the spring 9. A quick-release mechanism is provided on the outer side of the pressing rod 3. The quick-release mechanism includes a push spring 10, a push plate 11, a sleeve 12, a pressing groove 13, a movable plate 14, and a movable spring 15. One end of the push spring 10 is connected to the bottom end of the sleeve 12, and the other end of the push spring 10 is connected to the top end of the push plate 11. One side of the push plate 11 is in contact with the inner side of the base plate 2. One end of the movable spring 15 is connected to the bottom end of the pressing rod 3, and the other end of the movable spring 15 is connected to the movable plate 14. The movable plate 14 is fixedly connected to the sleeve 12. The sleeve 12 is fitted on the outside of the pressing rod 3, and the pressing groove 13 is opened on the side wall of the sleeve 12.

[0031] The quick-installation device, quick-release mechanism, and mounting holes 4 are provided at least four times, and the mounting holes 4 are designed with an asymmetrical structure.

[0032] In this embodiment, when the circuit board 1 needs to be installed, the circuit board 1 is first placed on the fixing sleeve 5 set on the base plate 2, and the mounting hole 4 is concentric with the fixing sleeve 5. Then, the retaining sleeve 12 is fixed by the retaining plate 16 to ensure that the retaining sleeve 12 does not move. Then, the pressing rod 3 is pressed down, so that the pressing rod 3 slides along the slide rail 17 and the slide groove 18. Due to the chamfer design of one side of the retaining block 7 and the inner wall of the pressing groove 13, the retaining block 7 will gradually be retracted into the storage groove 8, and the retaining block 7 will squeeze the spring 9 set in the storage groove 8. At the same time, one end of the pressing rod 3 will squeeze the movable spring 15 through the cooperation with the movable plate 14. When the movable spring 15 is squeezed to the limit, the outer side of the retaining block 7 is flush with the outer wall of the retaining sleeve 12, and the spring 9 is squeezed to the limit. Then, the ball bearing 19 is aligned with the guide groove 20 set in the fixing sleeve 5. Then, the retaining sleeve 12 is inserted into the inner side of the fixing sleeve 5 through the circuit board 1, and the outer side of the ball bearing 19 is flush with the outer wall of the retaining sleeve 12. After the inner wall of the guide groove 20 contacts, it will roll. Then, the bottom end of the push plate 11 connected to the push spring 10 at one end of the sleeve 12 will contact the bottom end of the inner wall of the fixed sleeve 5. Then, the sleeve 12 will continue to be inserted. The sleeve 12 will cooperate with the push plate 11 to squeeze the push spring 10. When the push spring 10 is squeezed to the limit, the sleeve 12 will press the circuit board 1 to the top of the fixed sleeve 5 through the clamping plate 16. The position of the compression groove 13 corresponds to the position of the clamping groove 6. At this time, the pressing rod 3 is released. The movable spring 15 pushes the pressing rod 3 to slide and reset along the slide rail 17 and the slide groove 18. Then, the pressing rod 3 drives the spring 9 and the clamping block 7 to move upward through the storage groove 8. Then, the clamping block 7 gradually aligns with the clamping groove 6. Then, the spring 9 gradually pushes the clamping block 7 out of the storage groove 8 and makes the clamping block 7 gradually slide into the clamping groove 6. When the spring 9 is fully reset, the clamping block 7 is fully inserted into the clamping groove 6. Then, the clamping plate 16 is no longer pressed, so that the circuit board 1 can be installed quickly.

[0033] Please see Figures 2-5 As a further implementation of the overall device: a card plate 16 is fixedly provided at the top of the card sleeve 12.

[0034] Both the inner walls of the card slot 6 and the extrusion groove 13 are designed with chamfered edges, and the lower side of the card block 7 is also chamfered.

[0035] The bottom of the push plate 11 is designed with a chamfered structure, and the top of the pressing rod 3 is rounded.

[0036] The inner wall of the sleeve 12 is fixedly provided with a slide rail 17, and the outer side of the pressing rod 3 is provided with a corresponding slide groove 18, which is adapted to the slide rail 17.

[0037] Multiple balls 19 are tumblingly mounted on the outer side of the sleeve 12, and a guide groove 20 is provided on the inner side of the fixing sleeve 5, with the balls 19 rolling within the guide groove 20.

[0038] The diameter of push spring 10 is larger than that of movable spring 15, and the number of turns of push spring 10 is greater than that of movable spring 15.

[0039] More specifically, when it is necessary to disassemble circuit board 1, press down on the pressing rod 3 directly, causing the pressing rod 3 to move along the slide rail 17 and the slide groove 18. Since the sleeve 12 presses the circuit board 1 tightly through the clamping plate 16, the sleeve 12 and the clamping plate 16 will not move. Then, the top of the inner wall of the storage groove 8 opened on the inner side of the pressing rod 3 presses down on the clamping block 7, causing the clamping block 7 and the spring 9 to move downward with the storage groove 8. Due to the chamfered design on the lower side of the clamping block 7, as well as the chamfered design at the lower end of the inner wall of the groove 6 and the lower end of the inner wall of the compression groove 13, the clamping block 7 is then compressed, and the clamping block 7 will gradually... The card gradually slides out of the slot 6 and into the storage slot 8. At the same time, the other side of the card block 7 will press against the card block 7 in the storage slot 8. Simultaneously, the pressing rod 3 will cooperate with the movable plate 14 set inside the sleeve 12 to press the movable spring 15. Then, when the spring 9 is compressed to its limit, the outer side of the card block 7 is flush with the outer wall of the sleeve 12, and part of the card block 7 is still in the compression groove 13. Then, the pressing rod 3 is released. Since the number of turns and the diameter of the push spring 10 are larger than those of the movable spring 15, and due to the setting of the slide rail 17 and the slide groove 18, the contact surface between the outer wall of the pressing rod 3 and the inner wall of the sleeve 12 is... The increased friction causes the movable spring 15 to reset more slowly. Furthermore, the ball bearings 19 on the outer side of the sleeve 12 roll within the guide groove 20 on the inner side of the fixed sleeve 5, reducing the sliding friction on the outer side of the sleeve 12 and allowing it to slide more smoothly. Then, the push spring 10 pushes the sleeve 12 to its sliding reset position. The sleeve 12 then causes the outer ball bearings 19 to roll along the guide groove 20. The sleeve 12 no longer presses the circuit board 1 against the fixed sleeve 5 via the clamping plate 16, and it then drives the inner pressing rod 3 and clamping block 7, among other components. Slide upwards, and then pull the sleeve 12 upwards directly through the card plate 16. Then the outer side of the card block 7 is no longer limited by the inner wall of the fixed sleeve 5. Then the movable spring 15 pushes the pressing rod 3 to slide and reset along the slide rail 17 and the slide groove 18. Then the pressing rod 3 will drive the spring 9 and the card block 7 set in the storage groove 8 to slide and reset. Since the outer side of the card block 7 is no longer limited, the spring 9 pushes the card block 7 to gradually slide out of the storage groove 8. Then the circuit board 1 is removed, thus achieving quick removal of the circuit board 1 without the aid of tools by simple pressing and pulling actions.

[0040] In summary, during the use or operation of the overall equipment: When it is necessary to install the circuit board 1, first place the circuit board 1 on the fixing sleeve 5 set on the base plate 2, and make the mounting hole 4 concentric with the fixing sleeve 5. Then, fix the sleeve 12 by the clamping plate 16 to ensure that the sleeve 12 does not move. Then, press the pressing rod 3 down, so that the pressing rod 3 slides along the slide rail 17 and the slide groove 18. Due to the chamfer design of one side of the clamping block 7 and the inner wall of the pressing groove 13, the clamping block 7 will gradually retract into the receiving groove 8, and the clamping block 7 will compress the spring 9 set in the receiving groove 8. At the same time, one end of the pressing rod 3 will compress the movable spring 15 through the cooperation with the movable plate 14. When the movable spring 15 is compressed to the limit, the outer side of the clamping block 7 is flush with the outer wall of the sleeve 12, and the spring 9 is compressed to the limit. Then, align the ball bearing 19 with the guide groove 20 set in the fixing sleeve 5, and then insert the sleeve 12 through the circuit board 1 into the inner side of the fixing sleeve 5. After the outer side of sleeve 19 contacts the inner wall of guide groove 20, it will roll. Then, the bottom end of push plate 11, which is connected to sleeve 12 via push spring 10, will contact the bottom end of inner wall of fixed sleeve 5. Then, sleeve 12 is inserted further, and sleeve 12 and push plate 11 will cooperate to squeeze push spring 10. When push spring 10 is squeezed to its limit, sleeve 12 will press circuit board 1 to the top of fixed sleeve 5 through clamping plate 16, and the position of compression groove 13 will correspond to the position of clamping groove 6. At this time, release the pressing rod 3. The movable spring 15 pushes the pressing rod 3 to slide and reset along the slide rail 17 and slide groove 18. Then, the pressing rod 3 drives the spring 9 and the locking block 7 to move upward through the storage groove 8. Then, the locking block 7 gradually aligns with the locking groove 6. Then, the spring 9 gradually pushes the locking block 7 out of the storage groove 8 and causes the locking block 7 to gradually slide into the locking groove 6. When the spring 9 is fully reset, the locking block 7 is fully locked into the locking groove 6. Then, the locking plate 16 is no longer pressed, which enables the rapid installation of the circuit board 1.

[0041] When it is necessary to disassemble circuit board 1, press down on the pressing rod 3 directly, causing the pressing rod 3 to move along the slide rail 17 and the slide groove 18. Since the retaining sleeve 12 presses the circuit board 1 tightly through the retaining plate 16, the retaining sleeve 12 and the retaining plate 16 will not move. Then, the top of the inner wall of the storage groove 8 opened on the inner side of the pressing rod 3 presses down on the retaining block 7, causing the retaining block 7 and the spring 9 to move downward with the storage groove 8. Due to the chamfered design on the lower side of the retaining block 7, as well as the chamfered design at the lower end of the inner wall of the retaining groove 6 and the lower end of the inner wall of the compression groove 13, the retaining block 7 is then compressed, and the retaining block 7 will gradually move out of the retaining groove. The spring 6 slides out and gradually enters the storage slot 8. At the same time, the other side of the locking block 7 will squeeze the locking block 7 in the storage slot 8. Simultaneously, the pressing rod 3 will cooperate with the movable plate 14 set inside the sleeve 12 to squeeze the movable spring 15. Then, when the spring 9 is squeezed to the limit, the outer side of the locking block 7 is flush with the outer wall of the sleeve 12, and part of the locking block 7 is still in the compression groove 13. Then the pressing rod 3 is released. Since the number of turns and the diameter of the push spring 10 are larger than those of the movable spring 15, and due to the setting of the slide rail 17 and the slide groove 18, the contact surface between the outer wall of the pressing rod 3 and the inner wall of the sleeve 12 is increased. This increases friction, causing the movable spring 15 to reset more slowly. The ball bearings 19 on the outer side of the sleeve 12 roll within the guide groove 20 on the inner side of the fixed sleeve 5, reducing sliding friction on the outer side of the sleeve 12 and allowing it to slide more smoothly. Then, the push spring 10 pushes the sleeve 12 to slide back to its original position. The sleeve 12 then causes the outer ball bearings 19 to roll along the guide groove 20. The sleeve 12 no longer presses the circuit board 1 against the fixed sleeve 5 via the clamping plate 16, and it causes the inner pressing rod 3 and clamping block 7 to move towards the fixed sleeve 5. Slide upwards, and then pull the sleeve 12 upwards directly through the card plate 16. Then the outer side of the card block 7 is no longer limited by the inner wall of the fixed sleeve 5. Then the movable spring 15 pushes the pressing rod 3 to slide and reset along the slide rail 17 and the slide groove 18. Then the pressing rod 3 will drive the spring 9 and the card block 7 set in the storage groove 8 to slide and reset. Since the outer side of the card block 7 is no longer limited, the spring 9 pushes the card block 7 to gradually slide out of the storage groove 8, and then the circuit board 1 is removed. Thus, the circuit board 1 can be quickly removed without the aid of tools by simple pressing and pulling actions.

[0042] Of all the solutions mentioned above, those involving the connection between two components can be selected according to the actual situation, such as welding, bolt and nut connection, bolt or screw connection, or other known connection methods, which will not be elaborated here. For all the fixed connections mentioned above, welding is preferred. Although embodiments of this utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this utility model. The scope of this utility model is defined by the appended claims and their equivalents.

Claims

1. A laminated HDI circuit board, comprising a circuit board (1), characterized in that: The circuit board (1) has a base plate (2) on one side. A quick-release device is installed on the base plate (2). The quick-release device includes a pressing rod (3), a mounting hole (4), a fixing sleeve (5), a slot (6), a locking block (7), a storage groove (8), and a spring (9). The mounting hole (4) is opened on the circuit board (1). The fixing sleeve (5) is fixedly installed on the base plate (2). The slot (6) is opened inside the fixing sleeve (5). The storage groove (8) is opened inside the pressing rod (3). One side of the locking block (7) is connected to the inner wall of the compression groove (13) through the spring (9). A quick-release mechanism is provided on the outside of the pressing rod (3). The quick-release mechanism includes... Push spring (10), push plate (11), sleeve (12), extrusion groove (13), movable plate (14) and movable spring (15). One end of the push spring (10) is connected to the bottom end of the sleeve (12), and the other end of the push spring (10) is connected to the top end of the push plate (11). One side of the push plate (11) is in contact with the inner side of the base plate (2). One end of the movable spring (15) is connected to the bottom end of the pressing rod (3), and the other end of the movable spring (15) is connected to the movable plate (14). The movable plate (14) is fixedly connected to the sleeve (12). The sleeve (12) is sleeved on the outside of the pressing rod (3), and the extrusion groove (13) is opened on the side wall of the sleeve (12).

2. The laminated HDI circuit board according to claim 1, characterized in that: The quick-installation device, quick-release mechanism, and mounting holes (4) are provided in at least four parts, and the mounting holes (4) are designed with an asymmetrical structure.

3. The laminated HDI circuit board according to claim 1, characterized in that: The top of the sleeve (12) is fixedly provided with a card plate (16).

4. The laminated HDI circuit board according to claim 3, characterized in that: The inner walls of the card slot (6) and the extrusion groove (13) are both designed with chamfered structures, and the lower side of the card block (7) is also chamfered.

5. A laminated HDI circuit board according to any one of claims 1-4, characterized in that: The bottom of the push plate (11) is designed with a chamfered structure, and the top of the pressing rod (3) is rounded.

6. A laminated HDI circuit board according to claim 5, characterized in that: The inner wall of the sleeve (12) is fixedly provided with a slide rail (17), and the outer side of the pressing rod (3) is provided with a corresponding slide groove (18), which is adapted to the slide rail (17).

7. A laminated HDI circuit board according to claim 6, characterized in that: The outer side of the sleeve (12) is provided with a plurality of balls (19) that are rolled on it. The inner side of the fixing sleeve (5) is provided with a guide groove (20), and the balls (19) are rolled in the guide groove (20).

8. A laminated HDI circuit board according to claim 7, characterized in that: The diameter of the push spring (10) is larger than the diameter of the movable spring (15), and the number of turns of the push spring (10) is greater than the number of turns of the movable spring (15).

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