General fixing mechanism for printed circuit board

Abstract

The utility model discloses a universal fixing mechanism for a printed circuit board. The universal fixing mechanism comprises a plurality of supporting columns, a fixing frame, a guide plate, a clamping plate and a plurality of movable columns. The fixing frame is connected to the top of the supporting column. A plurality of guide holes which are uniformly distributed are formed in the guide plate; a clamping hole is formed in the clamping plate; the clamping plate is provided with a sliding hole, and the clamping plate can horizontally slide through the sliding hole. When the printed circuit board is fixed, the plurality of movable columns are clamped in the corresponding guide holes in a penetrating manner; then, the peripheral side of the printed circuit board is fixed through the fixing frame, the movable columns at the positions corresponding to the electronic components are pressed down and fall off, then the clamping plate is moved so that the inner walls of the clamping holes can tightly press the side walls of the movable columns which do not fall off, and therefore the tops of the movable columns which do not fall off bear the plane bottom of the printed circuit board. The universal fixing device is not limited to a specific PCB structure, the universal fixing function of various PCB structures is achieved, the bearing plane of each PCB does not need to be customized, time and labor are saved, and cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit board fixtures, in particular to a general fixing mechanism for printed circuit boards.

Background Art

[0002] When connecting electronic components to a printed circuit board (PCB), the bottom of the PCB board body is usually borne by a bearing plane, and then various electronic components are soldered on the top of the board body. However, existing PCBs often need to have electronic components on both sides. Since the first side already has an uneven structure due to the soldering of various components, when soldering the second side of the board body, the first side of the board body can no longer be borne by the bearing plane. Therefore, the existing PCB fixing method is to customize the bearing plane for the second side processing according to the different structures of the first side, that is, to make a hollow-out avoidance treatment on the bearing plane according to the components on the first side, so that the remaining plane part of the first side of the board body is pressed on the customized bearing plane. The defect of this fixing method is high cost. Each PCB structure needs to be customized with a bearing plane separately, resulting in time-consuming and laborious work.

[0003] In view of this, it is necessary to provide a general fixing mechanism for printed circuit boards to overcome the above defects.

Content of the Utility Model

[0004] The purpose of the utility model is to provide a general fixing mechanism for printed circuit boards, aiming to solve the problem that a customized bearing plane needs to be made separately during the processing of existing double-sided PCBs, and to realize the general fixing of multiple PCBs, that is, one fixing structure can adapt to multiple PCBs, saving time and effort and reducing costs.

[0005] To achieve the above purpose, the utility model provides a general fixing mechanism for printed circuit boards, including:

[0006] Several support columns;

[0007] A fixing frame, which is connected to the top of the support columns;

[0008] A guide plate, which is connected to the support columns and is arranged below the fixing frame; the guide plate is provided with a plurality of uniformly distributed guide holes;

[0009] A clamping plate, which is arranged below the guide plate; the clamping plate is provided with clamping holes corresponding to the guide holes one by one; the clamping plate is provided with sliding holes, and the support columns pass through the corresponding sliding holes; the clamping plate can slide horizontally through the sliding holes;

[0010] A plurality of movable columns, the shape of the movable columns is adapted to the shape of the guide holes and the shape of the clamping holes;

[0011] When fixing the printed circuit board, a plurality of the movable columns are inserted into the corresponding guide holes and clamped therein; then the peripheral side of the printed circuit board is fixed by the fixing frame, the movable columns at the positions corresponding to the electronic components are pressed down and fall, and then the clamping plate is moved so that the inner wall of the clamping hole presses the side wall of the movable column that has not fallen, so that the top of the movable column that has not fallen supports the flat bottom of the printed circuit board.

[0012] In a preferred embodiment, it also includes:

[0013] The bottom plate is arranged below the card plate and is provided with a lifting hole, and the support column is passed through the corresponding lifting hole; the bottom plate can be lifted and lowered along the support column through the lifting hole; the bottom plate is used to push the movable column upward into the guide hole and to receive the fallen movable column.

[0014] In a preferred embodiment, it further comprises: a fixing rod;

[0015] The fixing frame is rectangular and includes two first side edges arranged opposite to each other and two second side edges arranged opposite to each other; first sliding grooves are provided on the inner sides of the two first side edges, and the two ends of the fixing rod extend into the two first sliding grooves respectively and can slide along the length direction of the first side edges.

[0016] In a preferred embodiment, a second slide groove is further provided at the top of each of the first sides, and the second slide groove is arranged parallel to and connected to the first slide groove on the same first side; locking holes are provided at both ends of the fixing rod; each of the first sides is provided with a locking accessory, and the locking accessory is used to lock the fixing rod at the target position of the first side.

[0017] In a preferred embodiment, the locking accessory comprises a first knob and a first screw disposed at the bottom of the first knob; the first knob is disposed at the top of the second slide slot, the first screw extends into the second slide slot and is screwed to the corresponding locking hole;

[0018] In a preferred embodiment, a buffer washer is provided on the inner side of the fixing frame, and the buffer washer is attached and fixed to the inner sides of the first side edge and the second side edge.

[0019] In a preferred embodiment, the guide plate is provided with a fixing hole; the side of the support column is provided with a first step and a second step, and the cross-sectional area of ​​the second step is larger than the cross-sectional area of ​​the first step; the fixing hole is sleeved on the first step, and the sliding hole is sleeved on the second step and can move horizontally along the second step.

[0020] In a preferred embodiment, a driving block is provided at the edge of the guiding plate, and a pushing member is provided on the driving block. The pushing block is used to push the clamping plate to move relative to the guiding plate.

[0021] In a preferred embodiment, the driving block is provided with a threaded hole, and the central axis of the threaded hole is located in the plane where the clamping plate is located; the pushing member includes a second knob and a second screw rod provided on one side of the second knob; one end of the second screw rod away from the second knob is threadedly passed through the threaded hole and abuts against the side surface of the clamping plate.

[0022] In a preferred embodiment, the movable post includes a column body and a thimble perpendicularly provided at one end of the column body; two annular limiting grooves are provided on the column body along the circumferential direction, and the two limiting grooves are arranged at intervals up and down; an elastic ring is sleeved in each limiting groove; the elastic ring on the side close to the thimble is used for interference fit with the inner wall of the guiding hole, and the other elastic ring is used for abutting against the inner wall of the clamping hole.

[0023] The general fixing mechanism for printed circuit boards provided by the present utility model forms a bearing plane for carrying the PCB board body by the tops of a plurality of movable posts inserted and clamped in corresponding guiding holes. When the operator fixes the side of the PCB through the fixing frame, the protruding electronic components on the PCB will exert pressure on the touched movable posts, causing them to disengage from the guiding holes and fall off, while the remaining planar part of the PCB continues to maintain the abutting state with the tops of the remaining movable posts. At this time, the clamping plate is pushed to make the inner wall of the clamping hole press against the side walls of the remaining non-fallen movable posts, thereby fixing the remaining non-fallen movable posts so that they will not fall off from the guiding holes again under pressure during processing, realizing the fixing of the PCB board body, thereby facilitating the subsequent electronic component soldering operation for the operator. Therefore, this fixing structure is not limited to a specific PCB structure, realizing the general fixing function for various PCB structures, without the need to customize the bearing plane for each type of PCB, saving time and effort and reducing costs.

Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a three-dimensional view of the general fixing mechanism for printed circuit boards provided by the present utility model;

[0026] Figure 2 is Figure 1Top view of the general fixing mechanism for the printed circuit board shown

[0027] Figure 3 is Figure 1 Side view of the general fixing mechanism for the printed circuit board shown

[0028] Figure 4 is Figure 1 Exploded perspective view of the general fixing mechanism for the printed circuit board shown

[0029] Figure 5 is Figure 1 Exploded perspective view of the fixing frame in the general fixing mechanism for the printed circuit board shown

[0030] Figure 6 is Figure 1 Perspective view of the movable post in the general fixing mechanism for the printed circuit board shown

[0031] Reference numerals in the figure: 100, general fixing mechanism for the printed circuit board;

[0032] 10, support post; 101, first connection hole; 11, first step; 12, second step;

[0033] 20, fixing frame; 201, second connection hole; 202, first sliding groove; 203, second sliding groove; 21, first side; 22, second side; 23, buffer washer;

[0034] 30, guide plate; 301, guide hole; 302, fixing hole; 31, driving block; 303, threaded hole;

[0035] 40, clamping plate; 401, clamping hole; 402, sliding hole;

[0036] 50, movable post; 501, limiting groove; 51, column body; 52, ejector pin; 53, elastic ring;

[0037] 60, fixing rod; 601, locking hole;

[0038] 70, bottom plate; 701, lifting hole.

Detailed implementation manners

[0039] In order to make the purpose, technical solution and beneficial technical effects of the present utility model clearer and more understandable, the present utility model will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners. It should be understood that the specific implementation manners described in this specification are only for explaining the present utility model and not for limiting the present utility model.

[0040] It should also be understood that the terms used in the description of the present utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. As used in the description of the present utility model and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0041] It should be further understood that the term "and / or" used in the description of the present utility model and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0042] In an embodiment of the present utility model, a general fixing mechanism 100 for a printed circuit board is provided, which is used to fix the board body of a printed circuit board (PCB), especially one side on which electronic components have been soldered, so as to facilitate the operator to perform processing operations on the blank side.

[0043] As Figures 1 - 4 shown, the general fixing mechanism 100 for a printed circuit board includes: a plurality of support columns 10, a fixing frame 20, a guide plate 30, a clamping plate 40, and a plurality of movable columns 50.

[0044] In this embodiment, the number of support columns 10 is four, which are respectively located at the four vertices of the same rectangle and are used to be placed on the operation plane.

[0045] Specifically, the fixing frame 20 is connected to the top of the support column 10. Among them, a first connection hole 101 may be opened at the top of the support column 10, and a second connection hole 201 corresponding to the first connection hole 101 is opened at the edge of the fixing frame 20. The second connection hole 201 is aligned with the first connection hole 101, and the fixing frame 20 is detachably installed on the top of the support column 10 through screws or the like.

[0046] Furthermore, as Figure 5 shown, the general fixing mechanism 100 for a printed circuit board further includes a fixing rod 60.

[0047] In this embodiment, the fixing frame 20 is rectangular, and includes two first side edges 21 arranged oppositely and two second side edges 22 arranged oppositely. It should be noted that the first side edge 21 and the second side edge 22 can be specified according to needs, and are only for facilitating the description of the structure of the fixing frame 20, and do not constitute a specific limitation on the fixing frame 20.

[0048] A first chute 202 is provided on the inner side of each of the two first side edges 21. Both ends of the fixing rod 60 extend into the two first chutes 202 respectively and can slide along the length direction of the first side edge 21. That is, the fixing rod 60 is arranged parallel to the two second side edges 22 and is located in the same plane. When it is necessary to fix the side of the PCB, two sides of the PCB can be abutted against the right angle formed by a first side edge 21 and a second side edge 22 to realize the positioning of the PCB; then the fixing rod 60 is driven to move along the length direction of the first chute 202 until it abuts against the third side of the PCB, so as to jointly clamp the three side edges of the PCB, realizing the fixation of the PCB on the horizontal plane.

[0049] Furthermore, a second chute 203 is also provided at the top of each of the first side edges 21. The second chute 203 is arranged parallel to and communicated with the first chute 202 provided on the same first side edge 21. That is, the opening of the second chute 203 faces the vertical direction, while the opening of the first chute 202 faces the horizontal direction. Locking holes 601 are provided at both ends of the fixing rod 60. Each first side edge 21 is provided with a locking accessory (not shown in the figure), and the locking accessory is used to lock the fixing rod 60 at the target position on the first side edge 21, so as to fasten the final position of the fixing rod 60 and prevent the PCB from moving horizontally.

[0050] Among them, the locking accessory includes a first knob and a first screw provided at the bottom of the first knob. The first knob is arranged at the top of the second chute 203 and adheres to the surface of the first side edge 21. The first screw extends into the second chute 203 and is screwed with the corresponding locking hole 601. After the fixing rod 60 moves to the position of clamping the side of the PCB, the operator can tighten the first knob to make the first knob tightly press against the surface of the first side edge 21, that is, by increasing the friction force to limit the movement of the fixing rod 60 in the first chute 202.

[0051] Furthermore, a buffer washer 23 is provided on the inner side of the fixing frame 20. The buffer washer 23 is fixedly attached to the inner sides of the first side edge 21 and the second side edge 22. The buffer washer 23 can be a silica gel ring or a rubber ring. When the side of the PCB is fixed, the buffer washer 23 abuts against the side of the PCB, which can provide a certain buffer, avoid damage to the PCB caused by excessive stress when the PCB is fixed in the horizontal direction, and at the same time increase the friction force on the side of the PCB to prevent the PCB from sliding easily in the horizontal plate direction. Among them, the buffer washer 23 is provided with a hollow avoidance treatment at the position corresponding to the first chute 202 to avoid affecting the movement of the fixing rod 60.

[0052] In the embodiment of the present utility model, the guide plate 30 is connected to the support column 10 and is spaced below the fixing frame 20. The guide plate 30 is provided with a plurality of uniformly distributed guide holes 301. Here, the guide holes 301 are exemplarily cylindrical holes and are uniformly densely paved on the guide plate 30.

[0053] The pallet 40 is disposed below the guide plate 30. The pallet 40 is provided with card holes 401 corresponding one-to-one to the guide holes 301. The shape of the card holes 401 is consistent with that of the guide holes 301 and they are arranged in alignment. That is, one movable column 50 can pass through the corresponding card hole 401 and the guide hole 301 simultaneously.

[0054] Wherein, the pallet 40 is further provided with sliding holes 402. The support columns 10 are inserted into the corresponding sliding holes 402. The pallet 40 can slide horizontally through the sliding holes 402.

[0055] Specifically, fixing holes 302 are formed at the edge of the guide plate 30. The side surface of the support column 10 is provided with a first step 11 and a second step 12, and the cross-sectional area of the second step 12 is larger than that of the first step 11. The fixing holes 302 are sleeved on the first step 11, thereby fixing the guide plate 30 on the plurality of support columns 10. The sliding holes 402 are sleeved on the second step 12 and can move horizontally along the second step 12. Among them, in an exemplary embodiment, the second step 12 includes a pair of vertical surfaces, and the sliding holes 402 are strip-shaped holes having a pair of straight edges, and the pair of straight edges respectively abut against the pair of vertical surfaces, so that the length of the sliding holes 402 is slightly larger than the cross-sectional length of the second step 12, and further enables the pallet 40 to move horizontally in a certain stroke relative to the second step 12 through the sliding holes 402.

[0056] Combined with Figure 6 As shown, the shape of the movable column 50 is adapted to the shape of the guide hole 301 and the shape of the card hole 401. In this embodiment, the guide hole 301 and the card hole 401 are cylindrical holes, and the main body of the movable column 50 is a cylinder. It should be noted that in order to avoid the lines of the attached drawings from being unclear due to all the shown movable columns 50, only a few movable columns 50 are shown in the drawings, and in actual use, an activity column 50 is provided for all the guide holes 301 or all the guide holes 301 within a partial predetermined range.

[0057] Specifically, the movable column 50 includes a column body 51 and a thimble 52 vertically disposed at one end of the column body 51. The column body 51 is provided with two annular limiting grooves 501 along the circumferential direction, and the two limiting grooves 501 are arranged at intervals up and down. An elastic ring 53 is sleeved in each limiting groove 501, and the surface of the elastic ring 53 slightly protrudes from the surface of the column body 51. The elastic ring 53 on the side close to the thimble 52 is used for interference abutting against the inner wall of the guide hole 301, so that when the column body 51 is clamped in the guide hole 301, a certain frictional force can be provided to prevent the movable column 50 from falling when no pressure is applied. The other elastic ring 53 is used for abutting against the inner wall of the card hole 401, and the elastic ring 53 can improve the roughness of the column body 51 itself.

[0058] Therefore, when it is necessary to fix a printed circuit board (PCB), a plurality of movable posts 50 are inserted and clamped into corresponding guiding holes 301; then the periphery of the printed circuit board is fixed by a fixing frame 20. At this time, the downwardly protruding electronic components will touch the movable posts 50, causing the corresponding movable posts 50 to be pressed down and fall off. The remaining movable posts 50 that have not fallen off all correspond to the flat part of the PCB bottom where no electronic components are provided. Then, the clamping plate 40 is moved so that the clamping holes 401 of the clamping plate 40 have a tendency to be misaligned with the guiding holes 301 of the guiding plate 30; since the inner wall of the clamping hole 401 and the surface of the column body 51 of the movable post 50 are both rough surfaces, and the inner wall of the clamping hole 401 also provides a horizontal pressure on the surface of the column body 51, the friction force between the inner wall of the clamping hole 401 and the surface of the column body 51 is very large, enabling the inner wall of the clamping hole 401 to tightly press the side wall of the non-fallen movable post 50. At this time, even if the top of the movable post 50 is further pressed down, the movable post 50 will not easily fall off, so that the top of the non-fallen movable post 50 bears the flat bottom of the printed circuit board, meeting the fixing requirements during PCB processing.

[0059] Further, as Figures 1 - 4 shown, the general fixing mechanism 100 for a printed circuit board further includes a bottom plate 70.

[0060] The bottom plate 70 is disposed below the clamping plate 40 and is provided with a lifting hole 701. The support column 10 is inserted into the corresponding lifting hole 701. The bottom plate 70 can be lifted along the support column 10 through the lifting hole 701. The bottom plate 70 is used to push the movable post 50 upward into the guiding hole 301 for initial reset. The bottom plate 70 is also used to receive the fallen movable posts 50. At this time, the bottom of the movable post 50 is vertically abutted against the bottom plate 70, and the upper half of the movable post 50 is also inserted into the clamping hole 401 and has been separated from the guiding hole 301, preventing the movable posts 50 from falling in a disorderly manner. It is convenient for the bottom plate 70 to directly push up later, and the fallen movable posts 50 can be directly clamped into the guiding holes 301, making the top of the movable posts 50 flush with the plane where the fixing frame 20 is located.

[0061] Combined with Figure 4 shown, in one embodiment, a driving block 31 is provided at the edge of the guiding plate 30. The driving block 31 faces the clamping plate 40. A pushing member (not shown in the figure) is provided on the driving block 31, and the pushing block is used to push the clamping plate 40 to move relative to the guiding plate 30.

[0062] Specifically, the driving block 31 is provided with a threaded hole 303, and the central axis of the threaded hole 303 is located on the plane where the card plate 40 is located. The pusher includes a second knob and a second screw rod disposed on one side of the second knob. One end of the second screw rod away from the second knob is threaded through the threaded hole 303 and abuts against the side of the card plate 40. When the card plate 40 is required to fix the movable column 50 that has not fallen, the second knob is tightened so that the second screw rod presses the card plate 40, so that the card plate 40 has a tendency to stagger relative to the guide plate 30.

[0063] In summary, the utility model provides a universal fixing mechanism 100 for printed circuit boards, by forming a bearing plane for bearing the PCB body through the tops of multiple movable columns 50 inserted and connected in the corresponding guide holes 301. When the operator fixes the side of the PCB through the fixing frame 20, the protruding electronic components on the PCB will exert pressure on the touched movable columns 50, so that they are disengaged from the guide holes 301 and then fall off, while the remaining plane portion of the PCB continues to maintain the abutment state with the top of the remaining movable columns 50. At this time, the card plate 40 is pushed so that the inner wall of the card hole 401 presses the side wall of the movable columns 50 that have not fallen off, thereby fixing the remaining movable columns 50 that have not fallen off, so that they will not fall off from the guide holes 301 when they are subjected to pressure during processing, thereby achieving the fixing of the PCB body, thereby facilitating the operator's subsequent electronic component welding operation. Therefore, the fixing structure is not limited to a specific PCB structure, and realizes the universal fixing function of multiple PCB structures, without the need to customize the bearing plane of each PCB, saving time and effort, and reducing costs.

[0064] The present invention is not limited to what is described in the specification and implementation modes, and therefore, additional advantages and modifications can be easily realized by those familiar with the art. Therefore, without departing from the spirit and scope of the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details, representative devices, and illustrative examples shown and described herein.

Claims

1. A universal fixing mechanism for a printed circuit board, characterized in that: include: Several support columns; A fixing frame connected to the top of the supporting column; A guide plate, the guide plate is connected to the support column and is arranged below the fixed frame; the guide plate is provided with a plurality of evenly distributed guide holes; A card plate, the card plate is arranged below the guide plate; the card plate is provided with card holes corresponding to the guide holes one by one; the card plate is provided with sliding holes, the support columns are passed through the corresponding sliding holes; the card plate can slide horizontally through the sliding holes; A plurality of movable columns, the shapes of which are adapted to the shapes of the guide holes and the clamping holes; When fixing the printed circuit board, a plurality of the movable columns are inserted into the corresponding guide holes and clamped therein; then the peripheral side of the printed circuit board is fixed by the fixing frame, the movable columns at the positions corresponding to the electronic components are pressed down and fall, and then the clamping plate is moved so that the inner wall of the clamping hole presses the side wall of the movable column that has not fallen, so that the top of the movable column that has not fallen supports the flat bottom of the printed circuit board.

2. The universal fixing mechanism for a printed circuit board according to claim 1, characterized in that: Also includes: A bottom plate, which is arranged below the card plate and has lifting holes, and the support columns are inserted into the corresponding lifting holes; The bottom plate can be lifted and lowered along the support column through the lifting hole; the bottom plate is used to push the movable column upward into the guide hole and receive the fallen movable column.

3. The universal fixing mechanism for a printed circuit board according to claim 1, characterized in that: Also includes: Fixed rod; The fixing frame is rectangular and includes two first side edges arranged opposite to each other and two second side edges arranged opposite to each other; A first sliding groove is provided on the inner sides of the two first side edges, and two ends of the fixing rod extend into the two first sliding grooves respectively and can slide along the length direction of the first side edge.

4. The universal fixing mechanism for a printed circuit board as claimed in claim 3, characterized in that: A second slide groove is also provided at the top of each of the first sides, and the second slide groove is arranged parallel to and connected to the first slide groove on the same first side; locking holes are provided at both ends of the fixing rod; each of the first sides is provided with a locking accessory, and the locking accessory is used to lock the fixing rod at a target position on the first side.

5. The universal fixing mechanism for a printed circuit board as claimed in claim 4, characterized in that: The locking accessory includes a first knob and a first screw rod arranged at the bottom of the first knob; the first knob is arranged at the top of the second sliding groove, and the first screw rod extends into the second sliding groove and is screwed with the corresponding locking hole.

6. The universal fixing mechanism for a printed circuit board as claimed in claim 3, characterized in that: A buffer washer is disposed on the inner side of the fixing frame, and the buffer washer is attached and fixed to the inner sides of the first side edge and the second side edge.

7. The universal fixing mechanism for a printed circuit board according to claim 1, characterized in that: The guide plate is provided with a fixing hole; the side of the support column is provided with a first step and a second step, and the cross-sectional area of ​​the second step is larger than the cross-sectional area of ​​the first step; the fixing hole is sleeved on the first step, and the sliding hole is sleeved on the second step and can move horizontally along the second step.

8. The universal fixing mechanism for a printed circuit board according to claim 1, characterized in that: A driving block is disposed at the edge of the guide plate, and a pushing member is disposed on the driving block. The pushing member is used to push the clamping plate to move relative to the guide plate.

9. The universal fixing mechanism for a printed circuit board as claimed in claim 8, characterized in that: The driving block is provided with a threaded hole, the central axis of which is located on the plane where the card plate is located; the pushing member includes a second knob and a second screw rod arranged on one side of the second knob; one end of the second screw rod away from the second knob is threaded through the threaded hole and abuts against the side surface of the card plate.

10. The universal fixing mechanism for a printed circuit board according to claim 1, characterized in that: The movable column includes a column and a pin vertically arranged at one end of the column; the column is provided with two annular limiting grooves along the circumferential direction, and the two limiting grooves are arranged at intervals up and down; an elastic ring is sleeved in each limiting groove; the elastic ring close to the side of the pin is used for interference fit with the inner wall of the guide hole, and the other elastic ring is used for abutting with the inner wall of the clamping hole.

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