Multiplex PCR (Polymerase Chain Reaction) quantitative detector

Abstract

The invention relates to the field of PCR detection, in particular to a multiplex PCR quantitative detector which comprises a quantitative detector body and a storage table extending to the front end of the quantitative detector body, a lower push seat and an upper push seat are slidably mounted on the rear portion of the upper end of the storage table, the upper push seat is located above the lower push seat, the upper push seat is elastically connected with the lower push seat, and the upper push seat is movably connected with the storage table. A sliding sleeve is slidably mounted on the side face of the lower pushing seat, a pushing frame is rotatably mounted between the upper end of the sliding sleeve and one side of the upper pushing seat, a fixing frame is fixedly mounted at the position, close to the edge, of the upper end of the storage table, a bag supporting piece is arranged on the fixing frame, and two L-shaped seats are symmetrically arranged on the side face of the fixing frame. The disposable receiving tray can adapt to detection of the sample liquid in the bag body, the use requirement is effectively met, and the phenomenon that the sample liquid in the bag body is continuously discharged and overflows out of the disposable receiving tray to pollute equipment is avoided.

Description

Technical Field

[0001] The present invention relates to the field of PCR detection, and in particular to a multiplex PCR quantitative detection instrument. Background Technology

[0002] Multiple PCR quantitative detection is based on common PCR technology, but multiple pairs of specific primers are added to the same reaction system. These primers can specifically bind to different regions of the template DNA, thereby amplifying multiple target fragments in the same reaction. Combined with detection methods such as fluorescent probes or fluorescent dyes, real-time quantitative detection of multiple targets can be achieved.

[0003] When the detection device is working, the detection straw in the device will extend and move down to insert into the sample liquid to absorb the sample liquid and allow it to enter the device for detection. For some volatile or easily contaminated samples, using a bag with good sealing properties for packaging can effectively prevent the volatilization or contamination of the sample and ensure the integrity of the sample. However, there are disadvantages in the detection of bagged samples. The sample liquid is wrapped in the bag, which makes it difficult for the detection device to absorb the sample liquid, that is, the phenomenon of being unable to detect occurs, so it is difficult to meet the needs of use. SUMMARY OF THE INVENTION

[0004] The purpose of the present invention is to solve the shortcomings of the background technology and propose a multiplex PCR quantitative detection instrument.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: a multiplex PCR quantitative detector, comprising a quantitative detector and a storage table extending at the front end of the quantitative detector, wherein a lower push seat and an upper push seat are slidably installed at the rear portion of the upper end of the storage table, respectively, wherein the upper push seat is located above the lower push seat, the upper push seat is elastically connected to the lower push seat, a sliding sleeve is slidably installed on the side of the lower push seat, a push frame is rotatably installed between the upper end of the sliding sleeve and one side of the upper push seat, and the upper end of the storage table is fixedly installed near the edge A fixing frame is provided, on which a bag holding member is provided, two L-shaped seats are symmetrically provided on the side of the fixing frame, a pressure plate is provided above the L-shaped seat, the pressure plate is connected to the push-down seat, a U-shaped seat is fixedly installed between the sides of the two L-shaped seats, a pull-out frame is extended from the front end of the sliding sleeve, and three upper clamping rings are fixedly installed at the end of the pull-out frame in a T-shaped distribution, a lower frame is slidably provided below the pull-out frame, the lower frame is slidably connected to the fixing frame, and three lower clamping rings are fixedly installed at the end of the lower frame in a T-shaped distribution.

[0006] Preferably, an extension frame is fixedly installed between the lower ends of the two L-shaped seats, and the end of the extension frame is fixed to the fixed frame. A plate frame is fixedly installed on the upper end of the pressure plate, and the end of the plate frame is fixed to the push-down seat. A square frame is slidably installed inside the sliding sleeve, and the square frame passes through both sides of the sliding sleeve, and the end of the square frame is fixed to the push-down seat.

[0007] Preferably, a carrier is fixedly mounted on the rear upper end of the storage table, two No. 2 slot columns are symmetrically fixedly mounted on the upper end of the carrier, the upper push seat and the lower push seat are slidably mounted on the surface of the No. 2 slot column, a spring body is wound around the outer side of the No. 2 slot column, one end of the spring body is fixed to the lower end of the upper push seat, and the other end of the spring body is fixed to the upper end of the lower push seat.

[0008] Preferably, a servo push cylinder is fixedly installed at the lower end of the storage table, and a pull rod is fixedly installed at the output end of the servo push cylinder. The pull rod passes through the storage table, the carrier, and the lower push seat in sequence. The pull rod is slidably connected with the storage table, the carrier, and the lower push seat. The upper push seat is embedded in the end of the pull rod. An arc-shaped positioning edge extends from the upper corner of the storage table, and the opposite surfaces of the L-shaped seat and the pressure plate are provided with anti-slip grooves.

[0009] Preferably, a synchronous column is fixedly mounted on the rear end of the lower frame, the pull-out frame is slidably mounted on the outer surface of the synchronous column, a guide frame is fixedly mounted on the lower end of the lower frame, a guide sleeve is slidably mounted on the outer surface of the guide frame, and the end of the guide sleeve is fixed to the fixed frame.

[0010] Preferably, the bag holding member comprises a plate shaft rotatably mounted on the end of the fixing frame, the outer surface of the plate shaft is inlaid with a bag holding plate, the bag holding plate is inclined downward, and the upper end of the bag holding plate has two limiting edges extending symmetrically.

[0011] Preferably, a gear is coaxially inlaid on the rear end of the plate shaft, a toothed plate is meshed on the side of the gear, the toothed plate is elastically connected to the fixing frame, a push claw is arranged above the toothed plate, and the end of the push claw is fixed to the other side of the upper push seat.

[0012] Preferably, a No. 1 slot column is fixedly installed in the middle of the tooth plate, a column frame is slidably installed on the outer surface of the No. 1 slot column, the end of the column frame is fixed to the fixed frame, a return spring is wound around the outer side of the No. 1 slot column, the upper end of the return spring is fixed to the tooth plate, the lower end of the return spring is fixed to the upper end of the column frame, and a column cap is coaxially inlaid at the lower end of the No. 1 slot column, and the column cap is fitted to the lower end of the column frame.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Place the bag on the bag support plate. At this time, the bottom of the bag is located at the L-shaped seat, the discharge pipe is located in the U-shaped seat, and the pipe plug is located in the lower clamp ring. Then the upper push seat moves downward to push the lower push seat through the spring body, so that the pressure plate and the upper clamp ring on the lower push seat can move downward, so that the bottom of the bag can be clamped and fixed on the L-shaped seat by the pressure plate, and the upper clamp ring clamps the pipe plug in the lower clamp ring for fixing. Then the upper push seat continues to move downward. At this time, under the support of the L-shaped seat and the lower clamp ring, the lower push seat will remain stationary, and the upper push seat that continues to move downward will drive the push frame to move, so that the sliding sleeve slides on the square frame, and then drive the fixed pipe plug to move sideways, so as to pull the pipe plug out of the discharge pipe on the bag body, so that the sample liquid in the bag body can flow into the disposable receiving tray through the discharge pipe, so as to be sucked by the quantitative detector for detection, so as to adapt to the detection of the sample liquid in the bag body and meet its use requirements.

[0014] 2. With the bag support plate tilted downward, the sample liquid in the bag can be gathered at the top of the bag. After the tube plug is pulled out, the push claw on the upper push seat just contacts the tooth plate. At this time, the upper push seat continues to move downward, allowing the push claw to push the tooth plate, causing the gear to flip, and then driving the bag support plate to slowly flip up, allowing the sample liquid in the bag to flow to the discharge pipe for discharge, so as to achieve the purpose of controlling the discharge of the sample liquid, so as to avoid the continuous discharge of the sample liquid in the bag and overflow of the disposable receiving tray to pollute the equipment. Brief Description of the Figures

[0015] Figure 1 is a structural schematic diagram of a multiplex PCR quantitative detector of the present invention; Figure 2 It is a schematic diagram of a bag support plate of a multiplex PCR quantitative detector of the present invention; Figure 3 It is a schematic diagram of an L-shaped seat of a multiplex PCR quantitative detector of the present invention; Figure 4 It is a schematic diagram of the synchronization column of a multiplex PCR quantitative detector of the present invention; Figure 5 This is a schematic diagram of another viewing angle of the bag support plate of a multiplex PCR quantitative detector of the present invention; Figure 6 It is a schematic diagram of the gears of a multiplex PCR quantitative detector of the present invention; Figure 7 It is a schematic diagram of a storage platform of a multiplex PCR quantitative detection instrument of the present invention; Figure 8 This is a view of the placement of a bag body of a multiplex PCR quantitative detection instrument of the present invention; Figure 9 This is a schematic diagram of a bag body of a multiplex PCR quantitative detection instrument of the present invention.

[0016] In the figure: 1. quantitative detector; 2. storage table; 3. bag support plate; 4. limit edge; 5. fixed frame; 6. plate shaft; 7. extension frame; 8. L-shaped seat; 9. pressure plate; 10. plate frame; 11. lower push seat; 12. push claw; 13. sliding sleeve; 14. pull-out frame; 15. synchronous column; 16. lower clamp ring; 17. anti-slip pattern; 18. U-shaped seat; 19. disposable receiving plate; 20. guide sleeve; 21. guide frame ; 22, lower frame; 23, slot column No. 1; 24, column cap; 25, upper clamp ring; 26, column frame; 27, reset spring; 28, gear; 29, servo push cylinder; 30, pull rod; 31, carrier; 32, slot column No. 2; 33, square frame; 34, push frame; 35, upper push seat; 36, spring body; 37, arc-shaped positioning edge; 38, tooth plate; 39, bag body; 40, discharge pipe; 41, pipe plug. Specific implementation method

[0017] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0018] If Figure 1-Figure 9The multiple PCR quantitative detector shown in the figure comprises a quantitative detector 1 and a storage table 2 extending at the front end of the quantitative detector 1. The detection pipette in the quantitative detector 1 extends and moves downward to be inserted into the sample liquid to absorb the sample liquid so that it enters the interior of the quantitative detector 1 for detection. Since this detection operation is a prior art and has been widely used, it is not described in detail here. The rear part of the upper end of the storage table 2 is slidably mounted with a lower push seat 11 and an upper push seat 35, and the upper push seat 35 is located at the lower Above the push seat 11, the upper push seat 35 is elastically connected to the lower push seat 11, and a sliding sleeve 13 is slidably installed on the side of the lower push seat 11. The sliding sleeve 13 can drive the pull-out frame 14 to move sideways to pull the pipe plug 41 out of the discharge pipe 40 on the bag body 39. A push frame 34 is rotatably installed between the upper end of the sliding sleeve 13 and one side of the upper push seat 35. The push frame 34 can move under the drive of the upper push seat 35 to push the sliding sleeve 13. A fixing frame 5 is fixedly installed near the edge of the upper end of the storage table 2, and a fixing frame 5 is arranged on the fixing frame 5. There is a bag supporting part, and the fixing frame 5 plays a bearing role. Two L-shaped seats 8 are symmetrically arranged on the side of the fixing frame 5. A pressing plate 9 is arranged above the L-shaped seat 8. The L-shaped seat 8 and the pressing plate 9 play a role in clamping and fixing the bottom of the bag body 39. The vertical edge of the L-shaped seat 8 can block the bag body 39 so that the bag body 39 will not move sideways. The pressing plate 9 is connected to the push-down seat 11. A U-shaped seat 18 is fixedly installed between the sides of the two L-shaped seats 8. The U-shaped seat 18 plays a role in supporting the discharge pipe 40. The sliding sleeve 1 3 is extended with a pull-out frame 14 at the front end, and three upper clamping rings 25 are fixedly installed at the end of the pull-out frame 14 in a T-shaped distribution, and the pull-out frame 14 plays the role of supporting the upper clamping ring 25. A lower frame 22 is slidably arranged below the pull-out frame 14, and the lower frame 22 is slidably connected to the fixed frame 5. Three lower clamping rings 16 are fixedly installed at the end of the lower frame 22 in a T-shaped distribution, and the lower frame 22 plays the role of supporting the lower clamping ring 16. The lower clamping ring 16 and the upper clamping ring 25 are distributed in a T-shape, which can adapt to the shape of the pipe plug 41 for clamping and fixing.

[0019] An extension frame 7 is fixedly installed between the lower ends of the two L-shaped seats 8, and the end of the extension frame 7 is fixed to the fixed frame 5, and the extension frame 7 plays a role in fixing the L-shaped seat 8. A plate frame 10 is fixedly installed on the upper end of the pressure plate 9, and the end of the plate frame 10 is fixed to the lower push seat 11, and the plate frame 10 plays a role in fixing the pressure plate 9. A square frame 33 is slidably installed inside the sliding sleeve 13, and the square frame 33 penetrates from both sides of the sliding sleeve 13. The end of the square frame 33 is fixed to the lower push seat 11, and the square frame 33 plays a role in allowing the sliding sleeve 13 to slide.

[0020] A carrier 31 is fixedly installed at the rear of the upper end of the storage table 2. Two No. 2 slot columns 32 are symmetrically fixedly installed on the upper end of the carrier 31. The carrier 31 plays a role in supporting and fixing the No. 2 slot columns 32. The upper push seat 35 and the lower push seat 11 are slidably installed on the surface of the No. 2 slot columns 32. The No. 2 slot columns 32 play a role in allowing the upper push seat 35 and the lower push seat 11 to slide. A spring body 36 is wrapped around the outer side of the No. 2 slot column 32. One end of the spring body 36 is fixed to the lower end of the upper push seat 35, and the other end of the spring body 36 is fixed to the upper end of the lower push seat 11. The spring body 36 can ensure that the upper push seat 35 moves down normally when the lower push seat 11 remains stationary.

[0021] A servo push cylinder 29 is fixedly installed at the lower end of the storage table 2, and a pull rod 30 is fixedly installed at the output end of the servo push cylinder 29. The servo push cylinder 29 drives the pull rod 30 to move. The pull rod 30 passes through the storage table 2, the carrier 31, and the lower push seat 11 in sequence. The pull rod 30 is slidably connected with the storage table 2, the carrier 31, and the lower push seat 11. The upper push seat 35 is embedded in the end of the pull rod 30. The pull rod 30 drives the upper push seat 35 to move up and down. An arc-shaped positioning edge 37 extends from the upper end corner of the storage table 2. The arc-shaped positioning edge 37 can position the disposable receiving tray 19 so that the sample liquid in the bag body 39 can flow into the disposable receiving tray 19 normally. The disposable design of the disposable receiving tray 19 can avoid sample liquid contamination. The opposite surfaces of the L-shaped seat 8 and the pressure plate 9 are provided with anti-slip grooves 17. The anti-slip grooves 17 play a role in increasing the fixing force of the L-shaped seat 8 and the pressure plate 9 on the bag body 39.

[0022] The rear end of the lower frame 22 is fixedly mounted with a synchronization column 15, and the pull-out frame 14 is slidably mounted on the outer surface of the synchronization column 15. The synchronization column 15 allows the lower frame 22 and the pull-out frame 14 to move synchronously. The lower end of the lower frame 22 is fixedly mounted with a guide frame 21, and the outer surface of the guide frame 21 is slidably mounted with a guide sleeve 20. The end of the guide sleeve 20 is fixed to the fixed frame 5. The guide frame 21 and the guide sleeve 20 play a role in guiding the lower frame 22.

[0023] The bag holding member includes a plate shaft 6 rotatably mounted on the end of a fixing frame 5, and a bag holding plate 3 is inlaid on the outer surface of the plate shaft 6. The plate shaft 6 serves to allow the bag holding plate 3 to flip. The bag holding plate 3 tilts downward, allowing the sample liquid in the bag body 39 to gather at the top of the bag body 39. Two limiting edges 4 extend symmetrically from the upper end of the bag holding plate 3, and the limiting edges 4 serve to position the bag body 39.

[0024] The rear end of the plate shaft 6 is coaxially inlaid with a gear 28, and the side of the gear 28 is meshed with a tooth plate 38. The cooperation of the gear 28 and the tooth plate 38 can allow the bag support plate 3 to slowly flip up, so that the sample liquid in the bag body 39 can flow to the discharge pipe 40, and discharge an appropriate amount of sample liquid into the disposable receiving plate 19. The tooth plate 38 is elastically connected to the fixing frame 5. A push claw 12 is arranged above the tooth plate 38. The end of the push claw 12 is fixed to the other side of the upper push seat 35, and the push claw 12 plays a role in pushing the tooth plate 38.

[0025] A slot column 23 is fixedly installed in the middle of the tooth plate 38. The groove design on the slot column 23 can ensure that the tooth plate 38 will not rotate. A column frame 26 is slidably installed on the outer surface of the slot column 23. The end of the column frame 26 is fixed to the fixed frame 5. The cooperation between the column frame 26 and the slot column 23 guides the tooth plate 38. A reset spring 27 is wound around the outer side of the slot column 23. The upper end of the reset spring 27 is fixed to the tooth plate 38, and the lower end of the reset spring 27 is fixed to the upper end of the column frame 26. The reset spring 27 resets the tooth plate 38 after the movement. The lower end of the slot column 23 is coaxially inlaid with a column cap 24. The column cap 24 positions the reset position of the tooth plate 38, and the column cap 24 fits the lower end of the column frame 26.

[0026] During the test, the bag body 39 is placed on the bag supporting plate 3. At this time, the bottom of the bag body 39 is located at the L-shaped seat 8, the discharge pipe 40 is located in the U-shaped seat 18, and the pipe plug 41 is located in the lower clamp ring 16. At the same time, under the effect of the downward tilt of the bag supporting plate 3, the sample liquid in the bag body 39 will gather at the top of the bag body 39. Then the servo push cylinder 29 works to drive the upper push seat 35 on the pull rod 30 to move downward, so as to push the lower push seat 11 through the spring body 36, so that the lower push seat 11 can be pushed downward. The pressing plate 9 and the upper clamping ring 25 on the seat 11 can move downward, so that the bottom of the bag body 39 can be clamped and fixed on the L-shaped seat 8 by the pressing plate 9, and at the same time, the upper clamping ring 25 clamps the pipe plug 41 in the lower clamping ring 16 for fixing, and then the upper push seat 35 continues to move downward. At this time, under the support of the L-shaped seat 8 and the lower clamping ring 16, the lower push seat 11 will remain stationary, and the upper push seat 35 that continues to move downward will drive the push frame 34 to move, so that the sliding sleeve 13 slides on the square frame 33, and then The fixed tube plug 41 is driven to move sideways to pull the tube plug 41 out of the discharge tube 40 on the bag body 39. At this time, the push claw 12 on the upper push seat 35 just contacts the tooth plate 38, and then the upper push seat 35 continues to move downward, allowing the push claw 12 to push the tooth plate 38, so that the gear 28 flips, and then drives the bag support plate 3 to slowly flip up, so that the sample liquid in the bag body 39 can flow to the discharge tube 40 and discharge a proper amount of sample liquid into the disposable receiving tray 19, and then the upper push seat 35 moves upward to reset the bag support plate 3 to stop the discharge of the sample liquid in the bag body 39, and then the detection straw in the quantitative detector 1 extends and moves downward to be inserted into the disposable receiving tray 19 to absorb the discharged sample liquid and allow it to enter the interior of the quantitative detector 1 for detection, and then the upper push seat 35 continues to move upward and reset, and during the reset process, the tube plug 41 is reinserted into the discharge tube 40 and the fixation of the bag body 39 is loosened, and then the bag body 39 can be removed.

[0027] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and the specification only describe the principles of the present invention. The present invention may have various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention to be protected. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A multiplex PCR quantitative detector, comprising a quantitative detector (1) and a storage platform (2) extending at the front end of the quantitative detector (1), characterized in that: A lower push seat (11) and an upper push seat (35) are slidably mounted on the rear portion of the upper end of the storage platform (2), respectively. The upper push seat (35) is located above the lower push seat (11), and the upper push seat (35) is elastically connected to the lower push seat (11). A sliding sleeve (13) is slidably mounted on the side of the lower push seat (11), and a push frame (34) is rotatably mounted between the upper end of the sliding sleeve (13) and one side of the upper push seat (35). A fixing frame (5) is fixedly mounted near the edge of the upper end of the storage platform (2), and a bag holding member is arranged on the fixing frame (5). Two symmetrical sides of the fixing frame (5) are provided. An L-shaped seat (8) is provided above the L-shaped seat (8), the pressing plate (9) is connected to the lower push seat (11), a U-shaped seat (18) is fixedly installed between the sides of the two L-shaped seats (8), a pull-out frame (14) is extended from the front end of the sliding sleeve (13), the end of the pull-out frame (14) is fixedly installed with three upper clamping rings (25) in a T-shaped distribution, a lower frame (22) is slidably arranged below the pull-out frame (14), the lower frame (22) is slidably connected to the fixed frame (5), and the end of the lower frame (22) is fixedly installed with three lower clamping rings (16) in a T-shaped distribution.

2. A multiplex PCR quantitative detector according to claim 1, characterized in that: An extension frame (7) is fixedly installed between the lower ends of the two L-shaped seats (8), and the end of the extension frame (7) is fixed to the fixed frame (5). A plate frame (10) is fixedly installed on the upper end of the pressure plate (9), and the end of the plate frame (10) is fixed to the lower push seat (11). A square frame (33) is slidably installed inside the sliding sleeve (13), and the square frame (33) passes through both sides of the sliding sleeve (13), and the end of the square frame (33) is fixed to the lower push seat (11).

3. A multiplex PCR quantitative detector according to claim 1, characterized in that: A carrier (31) is fixedly installed at the rear upper end of the storage table (2), and two No. 2 slot columns (32) are symmetrically fixedly installed at the upper end of the carrier (31). The upper push seat (35) and the lower push seat (11) are slidably installed on the surface of the No. 2 slot column (32), and a spring body (36) is wound around the outer side of the No. 2 slot column (32), one end of the spring body (36) is fixed to the lower end of the upper push seat (35), and the other end of the spring body (36) is fixed to the upper end of the lower push seat (11).

4. A multiplex PCR quantitative detector according to claim 3, characterized in that: A servo push cylinder (29) is fixedly installed at the lower end of the storage table (2), and a pull rod (30) is fixedly installed at the output end of the servo push cylinder (29). The pull rod (30) passes through the storage table (2), the carrier (31), and the lower push seat (11) in sequence. The pull rod (30) is slidably connected with the storage table (2), the carrier (31), and the lower push seat (11). The upper push seat (35) is embedded in the end of the pull rod (30). An arc-shaped positioning edge (37) extends from the upper corner of the storage table (2), and the opposing surfaces of the L-shaped seat (8) and the pressure plate (9) are provided with anti-slip grooves (17).

5. A multiplex PCR quantitative detector according to claim 1, characterized in that: A synchronous column (15) is fixedly mounted on the rear end of the lower frame (22); the pull-out frame (14) is slidably mounted on the outer surface of the synchronous column (15); a guide frame (21) is fixedly mounted on the lower end of the lower frame (22); a guide sleeve (20) is slidably mounted on the outer surface of the guide frame (21); and an end of the guide sleeve (20) is fixed to the fixed frame (5).

6. A multiplex PCR quantitative detector according to claim 1, characterized in that: The bag holding member comprises a plate shaft (6) rotatably mounted on the end of a fixing frame (5); the outer surface of the plate shaft (6) is inlaid with a bag holding plate (3); the bag holding plate (3) is inclined downward, and two limiting edges (4) extend symmetrically from the upper end of the bag holding plate (3).

7. A multiplex PCR quantitative detector according to claim 6, characterized in that: A gear (28) is coaxially embedded at the rear end of the plate shaft (6), a toothed plate (38) is meshed on the side of the gear (28), the toothed plate (38) is elastically connected to the fixing frame (5), a push claw (12) is arranged above the toothed plate (38), and the end of the push claw (12) is fixed to the other side of the upper push seat (35).

8. A multiplex PCR quantitative detector according to claim 7, characterized in that: A No. 1 slot column (23) is fixedly installed in the middle of the tooth plate (38), a column frame (26) is slidably installed on the outer surface of the No. 1 slot column (23), the end of the column frame (26) is fixed to the fixed frame (5), a return spring (27) is wound around the outer side of the No. 1 slot column (23), the upper end of the return spring (27) is fixed to the tooth plate (38), the lower end of the return spring (27) is fixed to the upper end of the column frame (26), and a column cap (24) is coaxially inlaid at the lower end of the No. 1 slot column (23), and the column cap (24) is fitted to the lower end of the column frame (26).

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