Magnetic bead separation device for nucleic acid extraction

Abstract

The invention provides a magnetic bead separation device for nucleic acid extraction, comprising: a sleeve, the lower end of which is closed; the upper end of the sleeve is detachably connected with the shell, a magnetic bar is arranged in the shell, the position of the magnetic bar corresponds to that of the sleeve, and the diameter of the magnetic bar is smaller than the inner diameter of the sleeve; the lifting plate is connected with the upper end of the magnetic bar, and the lifting plate is movably connected to the inner side of the shell; and the handle is provided with a driving assembly for driving the lifting plate to move. The magnetic bead separating device has the beneficial effects that the lifting plate is moved downwards, the magnetic bars are inserted into the sleeves, the multiple sleeves are inserted into the deep-hole plate containing the nanometer magnetic beads, the magnetic beads in the deep-hole plate are adsorbed, the magnetic beads in multiple holes can be transferred at a time, the magnetic beads are transferred into new holes (containing reagents), the magnetic bars are moved upwards, and the magnetic bead separating device is shaken up and down; the magnetic beads are uniformly dispersed into the reagent in the holes, the sleeve is detached by holding the handle, and the subsequent magnetic bead adsorption operation can be carried out by replacing a new sleeve, so that the working efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of experimental equipment, and particularly relates to a magnetic bead separation device for nucleic acid extraction. Background Art

[0002] Nucleic acid extraction is a basic operation in clinical detection and scientific research. The magnetic bead method for extraction usually adds SiO2-coated Fe3O4 nanomagnetic beads into a deep well plate, and then binds nucleic acids under conditions such as low pH value (usually pH 5.2) and high concentration of guanidine hydrochloride. After magnetic sorting and washing, finally, high pH value (usually pH 8.0) and low salt solution are used to elute the nucleic acids from the magnetic beads.

[0003] The current manual method for separating magnetic beads from a deep well plate is to place the deep well plate on a magnetic rack containing a magnet, so that the magnetic beads are concentrated on the wall of the deep well plate close to the magnet. A pipette is used to avoid the magnetic beads and suck out or add different reagents for nucleic acid extraction. This method has a complex operation process, resulting in low work efficiency.

[0004] Another current method is the fully automatic instrument method. The instrument controls the magnetism of the plastic sleeve rod by controlling the magnetic rod to enter and exit the plastic sleeve. When the magnetic rod enters the sleeve, it can adsorb the magnetic beads, and when the magnetic rod moves out of the sleeve, it can elute the magnetic beads. By transferring the magnetic beads into different reagents, nucleic acid extraction is carried out. The problems of this method include: First, it relies on large instruments and has a high cost; Second, it is necessary to gather a sufficient number of samples, and the number of extracted samples cannot be flexibly controlled, resulting in insufficient flexibility in sample processing. Summary of the Invention

[0005] In view of this, the present invention aims to provide a magnetic bead separation device for nucleic acid extraction in order to solve at least one of the above partial technical problems.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows:

[0007] A magnetic bead separation device for nucleic acid extraction, comprising:

[0008] A sleeve, the lower end of the sleeve is closed;

[0009] A housing, the upper end of the sleeve is detachably connected to the housing. A magnetic rod is provided inside the housing, the position of the magnetic rod corresponds to that of the sleeve, and the diameter of the magnetic rod is smaller than the inner diameter of the sleeve;

[0010] A lifting plate, the lifting plate is connected to the upper end of the magnetic rod, and the lifting plate is movably connected to the inside of the housing;

[0011] A handle, a driving component for driving the lifting plate to move is provided on the handle.

[0012] Further, the number of the sleeves is multiple, the upper ends of the multiple sleeves are connected by a connecting plate, a first through hole corresponding to the sleeve is formed in the connecting plate, the width of the connecting plate is greater than the outer diameter of the sleeve, a T-shaped groove corresponding to the connecting plate and the sleeve is formed in the side surface of the lower end of the housing, and the sleeve is detachably connected to the inner side of the T-shaped groove through the connecting plate;

[0013] An installation groove is formed in the upper end of the housing, and a second through hole corresponding to the magnetic rod is formed in the bottom end of the installation groove.

[0014] Further, the upper edge of the first through hole adopts a chamfer structure;

[0015] A handle is fixedly arranged at one end of the connecting plate, and anti-slip lines are arranged on the handle.

[0016] Further, a positioning tube corresponding to the second through hole is fixedly arranged at the bottom end of the installation groove, the inner diameter of the positioning tube matches the diameter of the magnetic rod, and the lower end of the magnetic rod is located inside the positioning tube.

[0017] Further, a cover plate is further included, the cover plate closes the upper opening of the installation groove, a guide post is fixedly arranged on the lifting plate, a guide tube matched with the guide post is fixedly arranged on the cover plate, the guide post is installed inside the guide tube, and the upper end of the guide tube is fixedly connected with a handle.

[0018] Further, a baffle is fixedly arranged at the upper end of the guide post, an installation hole perpendicular to the guide post is formed in the baffle, the driving component is a plug rod, the plug rod is located inside the installation hole, the handle is a square tube, a closing plate is fixedly arranged at the lower end of the square tube, the closing plate is fixedly connected with the guide tube, the guide post and the baffle are located inside the handle, a strip-shaped hole corresponding to the installation hole is formed in the side wall of the handle, the plug rod is located inside the strip-shaped hole, and both ends of the plug rod protrude from the side wall of the handle.

[0019] Further, a compression spring is arranged between the baffle and the closing plate, and the compression spring is located outside the guide post;

[0020] A plug is arranged at the upper end of the square tube, the plug closes the upper end of the square tube, and the plug is detachably connected with the square tube.

[0021] Further, a limiting column is fixedly arranged at one end of the plug rod, the diameter of the limiting column is greater than the width of the strip-shaped hole, a limiting tube is arranged at the other end of the plug rod, the limiting tube is in threaded connection with the plug rod, the outer diameter of the limiting tube matches the diameter of the limiting column, a limiting hole is formed at the lower end of the strip-shaped through hole, and the diameter of the limiting hole matches the diameter of the limiting column.

[0022] Further, an installation boss corresponding to the installation groove is fixedly provided on the lower end surface of the cover plate. The installation boss is installed inside the installation groove, and the cover plate is in interference connection with the housing through the installation boss.

[0023] Further, an installation column is fixedly provided at the upper end of the magnetic rod. Two limiting structures are fixedly provided on the upper side wall of the installation column. The distance between the two limiting structures matches the thickness of the lifting plate. The limiting structure includes two limiting bosses.

[0024] A first jack corresponding to the installation column is opened on the lifting plate, and a first sliding hole corresponding to the limiting boss is opened on the lifting plate.

[0025] A second jack corresponding to the installation column is opened on the cover plate, and a second sliding hole corresponding to the limiting boss is opened on the cover plate.

[0026] A storage groove corresponding to the limiting boss is opened on the lower end surface of the installation boss.

[0027] Compared with the prior art, the magnetic bead separation device for nucleic acid extraction of the present invention has the following beneficial effects:

[0028] For the magnetic bead separation device for nucleic acid extraction of the present invention, move the lifting plate downward, insert the magnetic rod into the sleeve, insert multiple sleeves into the deep well plate containing nanometer magnetic beads, adsorb the magnetic beads in the deep well plate, and multiple holes of magnetic beads can be transferred at one time. Transfer the magnetic beads to a new hole (containing reagent). Move the magnetic rod upward, shake the magnetic bead separation device up and down to evenly disperse the magnetic beads into the reagent in the hole. Hold the handle to disassemble the sleeve, and replace the new sleeve to perform the subsequent magnetic bead adsorption operation, improving the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0030] Figure 1 is a schematic three-dimensional structure diagram of the device according to an embodiment of the present invention;

[0031] Figure 2 is a schematic three-dimensional structure diagram of the sleeve according to an embodiment of the present invention;

[0032] Figure 3 is a schematic three-dimensional structure diagram of the housing according to an embodiment of the present invention;

[0033] Figure 4 is a schematic three-dimensional structure diagram of the magnetic rod according to an embodiment of the present invention;

[0034] Figure 5Schematic diagram of the three-dimensional structure of the lifting plate according to the embodiment of the present invention;

[0035] Figure 6 According to the embodiment of the present invention Figure 5 Schematic diagram of the structure at position A in;

[0036] Figure 7 Schematic diagram of the three-dimensional structure of the handle according to the embodiment of the present invention;

[0037] Figure 8 According to the embodiment of the present invention Figure 7 Schematic diagram of the structure at position B in;

[0038] Figure 9 Schematic diagram of the first sectional structure of the device according to the embodiment of the present invention;

[0039] Figure 10 According to the embodiment of the present invention Figure 9 Schematic diagram of the structure at position C in;

[0040] Figure 11 Schematic diagram of the second sectional structure of the device according to the embodiment of the present invention;

[0041] Figure 12 According to the embodiment of the present invention Figure 11 Schematic diagram of the structure at position D in;

[0042] Figure 13 According to the embodiment of the present invention Figure 11 Schematic diagram of the structure at position E in.

[0043] Explanation of reference numerals:

[0044] 1. Housing; 2. Sleeve; 3. Cover plate; 4. Handle; 5. Limit post; 6. Magnetic rod; 7. Lifting plate; 8. Plug; 101. T-shaped groove; 102. Installation groove; 103. Positioning tube; 201. Connecting plate; 202. Handle; 203. Chamfer structure; 301. Installation boss; 302. Second jack; 303. Second sliding hole; 304. Storage groove; 401. Guide tube; 402. Limit hole; 403. Strip-shaped through hole; 501. Insert rod; 502. Limit tube; 601. Installation column; 602. Limit boss; 701. Guide post; 702. Baffle; 703. Installation hole; 704. Compression spring; 705. First jack; 706. First sliding hole. Detailed implementation manners

[0045] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0046] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0047] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0048] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0049] As Figures 1 to 13 shown, a magnetic bead separation device for nucleic acid extraction includes: a sleeve 2 with a closed lower end; a housing 1, the upper end of the sleeve 2 is detachably connected to the housing 1, a magnetic rod 6 is provided inside the housing 1, the position of the magnetic rod 6 corresponds to that of the sleeve 2, and the diameter of the magnetic rod 6 is smaller than the inner diameter of the sleeve 2; a lifting plate 7, the lifting plate is connected to the upper end of the magnetic rod 6, and the lifting plate 7 is movably connected to the inner side of the housing 1; a handle 4, and a driving assembly for driving the lifting plate 7 to move is provided on the handle 4.

[0050] The number of sleeves 2 is eight, each sleeve 2 is correspondingly provided with a magnetic rod 6, and the number of sleeves 2 is also 3 - 7. Adjusting the number of magnetic rods 6 according to the number of sleeves 2 improves the scope of application. The upper ends of multiple sleeves 2 are connected by a connecting plate 201, a first through hole corresponding to the sleeve 2 is opened on the connecting plate 201, the width of the connecting plate 201 is greater than the outer diameter of the sleeve 2, a T-shaped groove 101 corresponding to the connecting plate 201 and the sleeve 2 is opened on the side surface of the lower end of the housing 1, and the sleeve 2 is detachably connected to the inner side of the T-shaped groove 101 through the connecting plate 201; the sleeve is a structural member made of plastic.

[0051] An installation groove 102 is formed at the upper end of the housing 1, and a second through hole corresponding to the magnetic rod 6 is formed at the bottom end of the installation groove 102.

[0052] The upper edge of the upper end of the first through hole adopts a chamfer structure 203; one end of the connecting plate 201 is fixedly provided with a handle 202, and the handle 202 is provided with anti-slip lines.

[0053] A positioning tube 103 corresponding to the second through hole is fixedly provided at the bottom end of the installation groove 102. The inner diameter of the positioning tube 103 matches the diameter of the magnetic rod 6. The lower end of the magnetic rod 6 is located inside the positioning tube 103. The positioning tube 103 plays a role in positioning and guiding the lower end of the magnetic rod 6 to prevent it from shaking during the movement process.

[0054] It further includes a cover plate 3. The cover plate 3 closes the upper opening of the installation groove 102. A guide post 701 is fixedly provided on the lifting plate 7. A guide tube 401 matching the guide post 701 is fixedly provided on the cover plate 3. The guide post 701 is installed inside the guide tube 401. The upper end of the guide tube 401 is fixedly connected to the handle 4. The guide tube 401 plays a guiding role during the movement of the lifting plate 7, making the movement process more stable.

[0055] A baffle 702 is fixedly provided at the upper end of the guide post 701. An installation hole 703 perpendicular to the guide post 701 is formed on the baffle 702. The driving component is a plug rod 501 (the driving part can also be in the structure form of a motor lead screw). The plug rod 501 is located inside the installation hole 703. The handle 4 is a square tube. A closing plate is fixedly provided at the lower end of the square tube. The closing plate is fixedly connected to the guide tube 401. The guide post 701 and the baffle 702 are located inside the handle 4. A strip-shaped hole corresponding to the installation hole 703 is formed on the side wall of the handle 4. The plug rod 501 is located inside the strip-shaped hole. Both ends of the plug rod 501 protrude from the side wall of the handle 4.

[0056] A compression spring 704 is provided between the baffle 702 and the closing plate. The compression spring 704 is located outside the guide post 701; a plug 8 is provided at the upper end of the square tube. The plug 8 closes the upper end of the square tube. The plug 8 is detachably connected to the square tube.

[0057] A limit post 5 is fixedly provided at one end of the plug rod 501. The diameter of the limit post 5 is larger than the width of the strip-shaped hole. A limit tube 502 is provided at the other end of the plug rod 501. The limit tube 502 is threadedly connected to the plug rod 501. The outer diameter of the limit tube 502 matches the diameter of the limit post 5. A limit hole 402 is formed at the lower end of the strip-shaped through hole 403. The diameter of the limit hole 402 matches the diameter of the limit post 5. The limit post 5 and the limit tube 502 function to prevent the plug rod 501 from detaching from the installation hole 703.

[0058] When the magnetic rod 6 needs to adsorb the magnetic beads, move the insertion rod 501 downward. The insertion rod 501 drives the lifting plate 7 and the magnetic rod 6 to move downward. The magnetic rod 6 enters the sleeve 2. During this process, the compression spring 704 is compressed. Move the insertion rod 501 along the axial direction of the installation hole 703. The limit post 5 or the limit tube 502 is inserted into the limit hole 402 to limit the baffle 702. After the magnetic beads are transferred, move the insertion rod 501 to make the limit post 5 disengage from the limit hole 402. At this time, the baffle 702 moves upward and resets under the elastic force of the compression spring 704. The operation process is convenient and the use efficiency is improved.

[0059] An installation boss 301 corresponding to the installation groove 102 is fixedly provided on the lower end surface of the cover plate 3. The installation boss 301 is installed inside the installation groove 102. The cover plate 3 is in interference connection with the housing 1 through the installation boss 301.

[0060] An installation column 601 is fixedly provided at the upper end of the magnetic rod 6. Two limiting structures are fixedly provided on the upper side wall of the installation column 601. The distance between the two limiting structures matches the thickness of the lifting plate 7. The limiting structure includes two limiting bosses 602. A first jack 705 corresponding to the installation column 601 is opened on the lifting plate 7. A first sliding hole 706 corresponding to the limiting boss 602 is opened on the lifting plate 7. A second jack 302 corresponding to the installation column 601 is opened on the cover plate 3. A second sliding hole 303 corresponding to the limiting boss 602 is opened on the cover plate 3. A receiving groove 304 corresponding to the limiting boss 602 is opened on the lower end surface of the installation boss 301. The receiving groove 304 limits the upper limiting boss 602 of the magnetic rod 6 when it is in the use state.

[0061] The number of magnetic rods 6 that can be adjusted according to the number of sleeves 2 can move up and down with the lifting plate 7, broadening the application range of the device.

[0062] When a certain magnetic rod 6 is in the use state, the two limiting structures of the installation column 601 clamp the lifting plate 7. The distance between the two limiting structures is slightly smaller than the thickness of the lifting plate 7, and the lifting plate 7 can be clamped. At this time, the magnetic rod 6 can move together with the lifting plate 7.

[0063] When a certain magnetic rod 6 is in the idle state, rotate the installation column 601 to align the limiting boss 602 with the first jack 705 and the second jack 302. After the upper limiting boss 602 at the upper end of the installation column 601 passes through the second jack 302 by moving upward, rotate the installation column 601. The two limiting structures of the installation column 601 clamp the cover plate 3. The distance between the two limiting structures is slightly smaller than the thickness of the cover plate 3, and the cover plate 3 can be clamped. At this time, the magnetic rod 6 does not move together with the lifting plate 7.

[0064] Working process:

[0065] Adjust the corresponding number of magnetic rods 6 to be in the working state according to the number of sleeves 2. Move the lifting plate 7 downward, insert the magnetic rods 6 into the sleeves 2, insert multiple sleeves 2 into the deep well plate containing nano magnetic beads, adsorb the magnetic beads in the deep well plate, and transfer the magnetic beads in multiple wells at one time. Transfer the magnetic beads to a new well (containing reagents). Move the magnetic rods 6 upward, shake the magnetic bead separation device up and down to evenly disperse the magnetic beads into the reagents in other wells. After the transfer is completed, hold the handle 202 to disassemble the sleeves 2, and replace with new sleeves 2 to perform subsequent magnetic bead adsorption operations, improving work efficiency.

[0066] The present invention is applicable to 96-well deep well plates. 96-well deep well plates are generally used for automatic nucleic acid extractors, and corresponding reagents are pre-loaded in the wells in advance. This is a pre-loaded 96-well deep well plate with 16 reactions. Experimental personnel can use the present invention to purchase 96-well deep well plates, 8-channel sleeves, and corresponding reagents, and can flexibly layout the well plates by themselves.

[0067] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of each embodiment of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

[0068] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A magnetic bead separation device for nucleic acid extraction, characterized in that, Comprising: A casing (2), the lower end of the casing (2) being closed; A housing (1), the upper end of the casing (2) being detachably connected to the housing (1), a magnetic rod (6) being provided inside the housing (1), the magnetic rod (6) corresponding to the position of the casing (2), and the diameter of the magnetic rod (6) being smaller than the inner diameter of the casing (2); A lifting plate (7), the lifting plate (7) being connected to the upper end of the magnetic rod (6), and the lifting plate (7) being movably connected to the inside of the housing (1); A handle (4), a driving assembly for driving the lifting plate (7) to move being provided on the handle (4).

2. The magnetic bead separation device for nucleic acid extraction according to claim 1, wherein: The number of the casings (2) is multiple, the upper ends of the multiple casings (2) being connected by a connecting plate (201), a first through hole corresponding to the casing (2) being formed in the connecting plate (201), the width of the connecting plate (201) being greater than the outer diameter of the casing (2), a T-shaped groove (101) corresponding to the connecting plate (201) and the casing (2) being formed in the lower side surface of the housing (1), and the casing (2) being detachably connected to the inside of the T-shaped groove (101) through the connecting plate (201); An installation groove (102) being formed in the upper end of the housing (1), and a second through hole corresponding to the magnetic rod (6) being formed in the bottom end of the installation groove (102).

3. The magnetic bead separation device for nucleic acid extraction according to claim 2, wherein: The upper edge of the first through hole adopts a chamfer structure (203); One end of the connecting plate (201) is fixedly provided with a handle (202), and anti-slip lines are provided on the handle (202).

4. The magnetic bead separation device for nucleic acid extraction according to claim 2, wherein: A positioning tube (103) corresponding to the second through hole is fixedly provided at the bottom end of the installation groove (102), the inner diameter of the positioning tube (103) being matched with the diameter of the magnetic rod (6), and the lower end of the magnetic rod (6) being located inside the positioning tube (103).

5. The magnetic bead separation device for nucleic acid extraction according to claim 2, wherein: A cover plate (3) is further included, the cover plate (3) closing the upper opening of the installation groove (102), a guiding column (701) being fixedly provided on the lifting plate (7), a guiding tube (401) matched with the guiding column (701) being fixedly provided on the cover plate (3), the guiding column (701) being installed inside the guiding tube (401), and the upper end of the guiding tube (401) being fixedly connected to the handle (4).

6. The magnetic bead separation device for nucleic acid extraction according to claim 5, wherein: A baffle (702) is fixedly provided at the upper end of the guiding column (701), an installation hole (703) perpendicular to the guiding column (701) being formed in the baffle (702), the driving assembly being a plug rod (501), the plug rod (501) being located inside the installation hole (703), the handle (4) being a square tube, a closing plate being fixedly provided at the lower end of the square tube, the closing plate being fixedly connected to the guiding tube (401), the guiding column (701) and the baffle (702) being located inside the handle (4), a strip-shaped hole corresponding to the installation hole (703) being formed in the side wall of the handle (4), the plug rod (501) being located inside the strip-shaped hole, and both ends of the plug rod (501) protruding from the side wall of the handle (4).

7. The magnetic bead separation device for nucleic acid extraction according to claim 6, characterized in that: A compression spring (704) is provided between the baffle (702) and the closing plate, and the compression spring (704) is located outside the guiding column (701); A plug (8) is provided at the upper end of the square tube, the plug (8) closes the upper end of the square tube, and the plug (8) is detachably connected to the square tube.

8. A magnetic bead separation device for nucleic acid extraction according to claim 7, characterized in that: One end of the insertion rod (501) is fixedly provided with a limit post (5), the diameter of the limit post (5) is larger than the width of the strip-shaped hole, the other end of the insertion rod (501) is provided with a limit tube (502), the limit tube (502) is threadedly connected to the insertion rod (501), the outer diameter of the limit tube (502) matches the diameter of the limit post (5), a limit hole (402) is opened at the lower end of the strip-shaped through hole (403), and the diameter of the limit hole (402) matches the diameter of the limit post (5).

9. A magnetic bead separation device for nucleic acid extraction according to claim 5, characterized in that: An installation boss (301) corresponding to the installation groove (102) is fixedly provided on the lower end surface of the cover plate (3), the installation boss (301) is installed inside the installation groove (102), and the cover plate (3) is in interference connection with the housing (1) through the installation boss (301).

10. A magnetic bead separation device for nucleic acid extraction according to claim 9, characterized in that: An installation column (601) is fixedly provided at the upper end of the magnetic rod (6), two limit structures are fixedly provided on the upper side wall of the installation column (601), the distance between the two limit structures matches the thickness of the lifting plate (7), and the limit structure includes two limit bosses (602); A first jack (705) corresponding to the installation column (601) is opened on the lifting plate (7), and a first sliding hole (706) corresponding to the limit boss (602) is opened on the lifting plate (7); A second jack (302) corresponding to the installation column (601) is opened on the cover plate (3), and a second sliding hole (303) corresponding to the limit boss (602) is opened on the cover plate (3); A storage groove (304) corresponding to the limit boss (602) is opened on the lower end surface of the installation boss (301).

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