Sample tube sorting in-out sample mechanism

Abstract

The application provides a sample tube arrangement in-out sample mechanism, belonging to the technical field of automatic sample detection equipment, which comprises a blanking component and an arrangement component. An inclined guide slope is arranged at the bottom of the blanking component. The arrangement component is arranged on the low side close to the guide slope. A channel for accommodating the vertical lifting movement of the arrangement component is arranged at the bottom end of the blanking component. An anti-pipe jamming mechanism is arranged on the inner wall of the channel. The anti-pipe jamming mechanism comprises a forward correction component and a lateral correction component. Rails are arranged on both sides of the channel to adapt to the sliding of the arrangement component. The arrangement component is driven by a lifting and pulling driving assembly to make vertical reciprocating movement along the rails. An inclined guide slope is arranged at the bottom of the blanking component. The arrangement component is arranged on the low side close to the guide slope. A hollow arrangement cavity is arranged in the arrangement component. The problems of low arrangement and feeding efficiency in the prior art and the difficulty in meeting the high-speed sampling requirement can be solved.

Description

Technical Field

[0001] This invention belongs to the technical field of automated sample testing equipment, and more specifically, relates to a sample tube sorting and loading / unloading mechanism. Background Technology

[0002] With the rapid development of the in vitro diagnostics (IVD) industry, laboratory automation (Laboratory Automation) has become a key technology for improving testing efficiency and ensuring testing quality. Currently, the IVD industry is undergoing a transformation and upgrade from single-machine automation to full laboratory automation. The sample pretreatment system, as a core component of total laboratory automation (TLA), undertakes key functions such as sample receiving, centrifugation, cap removal, cupping, and classification. Its level of automation directly affects the throughput and reliability of the entire testing process. In the sample pretreatment process, the arrangement and loading / unloading of sample tubes is the primary step. Since vacuum blood collection tubes are usually randomly stacked during transportation and storage, with caps facing different directions, a specialized arrangement mechanism is needed to orient and transport the sample tubes one by one. In existing technologies, sample tube arrangement mechanisms mainly adopt a stepped transmission structure, using the tube body to lift at different levels of steps to coordinate with the track for sorting and orienting the sample tubes. However, multi-level stepped transmission mechanisms are complex and have low loading efficiency, and can only lift one tube at a single level, making it difficult to meet the sample loading speed requirements of high-throughput IVD analysis equipment. Summary of the Invention

[0003] In view of this, the present invention provides a sample tube sorting and feeding mechanism that can solve the problem of low sorting and feeding efficiency in the prior art, which makes it difficult to meet the requirements of high-speed sample feeding.

[0004] This invention is implemented as follows:

[0005] This invention provides a sample tube handling and feeding mechanism, comprising a feeding component and a handling component. The feeding component has an inclined guide slope at its bottom, and the handling component is located near the lower side of the guide slope. The bottom end of the feeding component has a channel for accommodating the vertical lifting and lowering movement of the handling component. An anti-jamming mechanism is provided on the inner wall of the channel, including a forward correction component and a lateral correction component. Guide rails adapted to the sliding of the handling component are provided on both sides of the channel, and the handling component is driven by a lifting drive assembly to perform vertical reciprocating motion along the guide rails.

[0006] The technical advantages of the sample tube sorting and loading / unloading mechanism provided by this invention are as follows: By setting a vertical lifting channel at the bottom of the feeding component and integrating the sorting component within this channel, an integrated design of feeding, sorting, and loading is achieved. The inclined guide surface utilizes gravity to achieve initial convergence and directional movement of the sample tubes. The vertical reciprocating motion of the sorting component within the channel completes the extraction and posture sorting of the sample tubes. Simultaneously, an anti-jamming mechanism, through the coordinated action of forward and lateral correction components, intervenes in sample tubes with abnormal postures during feeding (such as lateral bridging or oblique jamming), actively correcting their posture and ensuring they smoothly fall into the sorting component or return to the hopper for re-sorting. This integrated design eliminates the transfer link between the independent tube sorting machine and the loading hopper in traditional solutions, simplifying the process of sorting and correcting the posture of the sample tubes. Furthermore, the anti-jamming mechanism reduces the tube jamming failure rate and significantly improves the reliability of continuous equipment operation.

[0007] Based on the above technical solution, the sample tube sorting and loading / unloading mechanism of the present invention can be further improved as follows:

[0008] The feeding component has an inclined guide slope at its bottom, and the sorting component is located on the lower side of the guide slope. The sorting component has a hollow sorting cavity inside, the top of the sorting cavity is connected to the outside and the edge is provided with an inclined tube-sorting step, the higher side of the tube-sorting step is an inclined guide section, and the lower side is provided with a placement section.

[0009] The beneficial effects of adopting the above-mentioned improved scheme are as follows: By designing an inclined guide section on the tube-handling step surface, the sample tubes are made to automatically roll towards the placement section by utilizing the component of gravity of the sample tubes. During the rolling process, the diameter difference between the tube cap and the tube body is used to achieve initial posture adjustment. (The tube cap end is blocked by the edge of the inclined guide section due to its larger diameter, while the tube body end enters the handling chamber, thus making the sample tube ultimately present a vertical state with the tube cap facing upwards.) The adjustment action is completed synchronously with the lifting and lowering movement of the handling components, without taking up additional processing time.

[0010] Furthermore, the gap between the tubes of the sorting component is greater than the diameter of the sample tube body but smaller than the diameter of the sample tube cap.

[0011] The advantages of adopting the above-mentioned improved scheme are: it ensures that only the tube body can enter the sorting chamber through the tube sorting gap, while the tube cap is stuck on the tube sorting step surface, thereby achieving directional sorting of the sample tubes with the tube cap facing upwards and the tube body facing downwards. Furthermore, it can accommodate sample tubes of different lengths but with the same tube cap diameter, thus offering greater compatibility.

[0012] Furthermore, the lifting drive assembly includes a drive motor, a linear guide rail, and a trolley. The drive motor is fixedly mounted on the top of the linear guide rail, and its output end is connected to the drive wheel. Through a transmission belt, it works with the driven wheel at the bottom of the linear guide rail to drive the trolley to perform reciprocating lifting and lowering motion along the linear guide rail. The trolley is fixedly installed on one side of the sorting component through a T-shaped frame.

[0013] The beneficial effects of adopting the above-mentioned improved scheme are as follows: Belt drive has buffering and vibration absorption characteristics, and can smoothly drive the sorting component to rise and fall. Connecting the trolley and sorting component with a T-shaped frame ensures connection rigidity while providing installation space for the limiting and guiding structures of the sorting component, making the overall structure compact. Linear guide rails ensure the linear accuracy of the sorting component's lifting movement, enabling it to accurately align with the unloading channel and sample output station.

[0014] Furthermore, the feeding component is a sample tube feeding bin with storage space, and a bin cover is movably provided on one side of the outer end. The other end of the feeding component relative to the bin cover is provided with a through groove on the inner wall of the sorting component for accommodating and installing the positive correction component.

[0015] The beneficial effects of adopting the above-mentioned improved scheme are as follows: During use, operators can add sample tubes in batches by opening the hopper cover, preventing external contaminants from entering the hopper. The through-channel is located on the inner wall close to the sorting component, allowing the positive correction component to directly act on the sample tubes about to enter the sample dispensing station, implementing targeted intervention in the area with the highest risk of tube jamming, thus improving the effectiveness of tube jamming prevention.

[0016] Furthermore, the positive correction component includes multiple sets of wide springs, which are equally spaced along the through groove. The bottom side of the through groove is provided with a stepped surface for installing the wide springs, and the bottom end of the wide springs is fixed by bolts corresponding to the screw holes on the stepped surface.

[0017] The beneficial effects of adopting the above-mentioned improved scheme are as follows: By using multiple sets of wide spring clips in conjunction with inclined guide sections to form a gradient correction barrier, when the sample tube experiences lateral bridging or tilting jamming within the channel or at the edge, the elastic contact surfaces of the wide spring clips sequentially apply lateral pressure to the sample tube, gradually causing it to disengage and fall downwards. The isomorphically constructed stepped surface installation facilitates the deformation of the wide spring clips, preventing tube jamming and interference. The bolt fixing method facilitates the replacement and maintenance of the spring clips.

[0018] Furthermore, the lateral correction component is a set of narrow springs, which are disposed at the top of the guide rail near the side of the inclined guide section.

[0019] The beneficial effects of the above-mentioned improvement scheme are as follows: A narrow spring clip provides localized correction at specific tube jamming locations, namely the narrow area where the inclined guide section meets the top of the guide rail. Due to the confined space in this area, sample tubes are prone to corner jamming. The arc-shaped contact surface of the narrow spring clip gently pushes the sample tube away from the jamming location, allowing it to smoothly enter the sorting chamber. The combination of narrow and wide spring clips provides comprehensive protection against tube jamming faults of different locations and shapes within the channel, while not interfering with the reciprocating movement of the sorting components.

[0020] Furthermore, the side wall of the sorting component near the placement section is fixedly installed to the T-shaped frame by bolts. The T-shaped frame is provided with guide protrusions that are adapted to the guide rail. On the other side of the sorting component, opposite to the guide rail, multiple sets of circular limiting guide blocks are provided. The limiting guide blocks are fixedly installed to the side wall of the sorting component by bolts.

[0021] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the T-shaped frame and the side wall of the placement section of the sorting component are bolted together to ensure a reliable connection between the sorting component and the lifting drive system; the cooperation between the guide protrusion and the guide rail achieves precise guidance on one side of the sorting component. The limiting guide block on the opposite side wall adopts a circular structure and contacts the guide rail, which not only achieves limiting guidance on the other side, but also reduces lifting resistance, ensuring smooth lifting of the sorting component in the channel.

[0022] Furthermore, the top outer edge of the feeding component is provided with a folded edge, and a screw hole is provided on the folded edge. During installation, the feeding component is installed and fixed by aligning the screw hole on the folded edge with the mounting hole on the equipment. At this time, the top of the feeding component is closed, and only the sample outlet is left on the side near the sorting component. The anti-jamming mechanism is used to prevent the sample outlet from jamming.

[0023] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the folded edge is used to connect the feeding component with the main equipment for installation, and the screw hole connection facilitates the disassembly and maintenance of the equipment. During use, the structural design of the feeding component being closed at the top and using an opening on one side for sample dispensing allows the sample tubes to form a stable accumulation state in the hopper, flowing orderly only through the guide slope to the sample outlet, preventing external interference. The anti-jamming mechanism specifically addresses the risk of jamming in the sample outlet area, ensuring the reliability of sample dispensing.

[0024] Furthermore, the contact surface of the wide spring is an inclined plane. When interference sample tubes are piled up above the sorting component, lateral pressure can be applied sequentially through the contact surface of the wide spring to make them fall from above and prevent tube jamming. The contact surface of the lateral correction component is an arc-shaped surface to prevent the inclined guide section at the high position from jamming the tube at the contact position of the first set of wide springs.

[0025] The beneficial effects of the above-mentioned improved scheme are as follows: The oblique planar contact surface gives the force exerted by the wide spring on the sample tube a clear direction (obliquely downward), assisting in its downward detachment while pushing and clamping the tube, thus improving the tube clamping release efficiency. The arc-shaped contact surface makes the contact between the narrow spring and the sample tube gradual, better preventing damage to the spring in a limited space. The differentiation of the spring contact surface is used to address different tube clamping methods; the oblique planar surface is suitable for handling tube clamping caused by stacking and bridging, while the arc-shaped surface is suitable for handling tube clamping caused by corner jamming.

[0026] Compared with existing technologies, the beneficial effects of the sample tube sorting and loading / unloading mechanism provided by this invention are as follows: Through integrated structural design, the traditional separate functions of feeding, sorting, and loading are realized through a single mechanism. The coordinated action of the inclined guide slope, vertical lifting channel, and anti-jamming mechanism allows sample tubes to be fed from disordered locations, fall to the sorting component under their own gravity, and undergo posture correction and orientation sorting on the sorting step surface of the sorting component, resulting in orderly sample output and continuous automated processing. Specifically, the hollow sorting cavity and the sorting step surface of the sorting component utilize limiting and gravity to achieve passive automatic sorting of the sample tube cap orientation, eliminating the need for complex detection and adjustment mechanisms. The combined configuration of the forward correction component and the lateral correction component provides an elastic structural intervention barrier at key jamming risk points in the feeding channel, correcting abnormally oriented sample tubes and reducing the jamming failure rate. The T-shaped frame connection between the lifting drive component and the sorting component, along with the double-sided guide design, ensures precise and stable movement of the sorting component within the vertical channel, achieving reliable sample tube extraction and transport. The synergistic effect of the above-mentioned technical features fundamentally solves the technical problems of complex equipment structure and low processing efficiency in the existing technology; while improving efficiency, it reduces the area occupied inside the device, and meets the stringent requirements of high-throughput IVD analysis equipment for sample preprocessing speed and high reliability. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A three-dimensional structural diagram of a sample tube handling and feeding mechanism;

[0029] Figure 2 A schematic diagram of the sorting components of a sample tube sorting and inlet / outlet mechanism;

[0030] Figure 3A schematic diagram of the dynamic position of the sorting components of a sample tube sorting and inlet / outlet mechanism;

[0031] Figure 4 A side view of a sample tube handling and feeding mechanism;

[0032] Figure 5 A rear view of a sample tube handling and feeding mechanism;

[0033] The attached diagram lists the components represented by each number as follows:

[0034] 10. Feeding component; 101. Guide slope; 102. Channel; 11. Sorting component; 111. Sorting chamber; 112. Tube sorting step; 1121. Inclined guide section; 1122. Placement section; 113. Tube sorting gap; 12. Lifting drive assembly; 121. Drive motor; 122. Linear guide rail; 123. Trolley; 13. Anti-jamming mechanism; 131. Forward correction component; 1311. Wide spring; 132. Lateral correction component; 14. Guide rail; 15. Drive wheel; 16. Driven wheel; 17. Transmission belt; 18. T-shaped frame; 19. Bin cover; 20. Through groove; 201. Stepped surface; 21. Folded edge. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0036] like Figure 1 Figures 3 and 4 show an embodiment of a sample tube sorting and feeding mechanism provided by the present invention. In this embodiment, it includes a feeding component 10 and a sorting component 11. The feeding component 10 has an inclined guide slope 101 at its bottom. The sorting component 11 is located on the lower side near the guide slope 101. The bottom end of the feeding component 10 has a channel 102 for accommodating the sorting component 11 to perform vertical lifting and lowering movements. An anti-jamming mechanism 13 is provided on the inner wall of the channel 102. The anti-jamming mechanism 13 includes a forward correction component 131 and a lateral correction component 132. Guide rails 14 adapted to the sliding of the sorting component 11 are opened on both sides of the channel 102. The sorting component 11 is driven by the lifting drive assembly 12 to perform vertical reciprocating movements along the guide rails 14.

[0037] like Figure 2As shown, in the above technical solution, the bottom of the feeding component 10 is provided with an inclined guiding slope 101, and the sorting component 11 is provided on the lower side near the guiding slope 101; the sorting component 11 is provided with a hollow sorting cavity 111 inside, the top of the sorting cavity 111 is connected to the outside and the edge is provided with an inclined tube-sorting step surface 112, the higher side of the tube-sorting step surface 112 is an inclined guide section 1121, and the lower side is provided with a placement section 1122.

[0038] Furthermore, in the above technical solution, the tube-handling gap 113 of the sorting component 11 is greater than the tube body diameter of the sample tube and smaller than the tube cap diameter of the sample tube.

[0039] like Figure 5 As shown, in the above technical solution, the lifting drive assembly 12 includes a drive motor 121, a linear guide rail 122, and a trolley 123. The drive motor 121 is fixedly mounted on the top of the linear guide rail 122, and its output end is connected to the drive wheel 15. Through the transmission belt 17 and the driven wheel 16 at the bottom of the linear guide rail 122, the trolley 123 is driven to perform reciprocating lifting and lowering motion along the linear guide rail 122. The trolley 123 is fixedly installed on one side of the sorting component 11 through the T-shaped frame 18.

[0040] Furthermore, in the above technical solution, the unloading component 10 is a sample tube unloading bin with storage space, and a bin cover 19 is movably provided on one side of the outer end. The other end of the unloading component 10 relative to the bin cover 19 is close to the inner wall of the sorting component 11 and has a through groove 20 for accommodating and installing the positive correction component 131.

[0041] like Figure 3 As shown, in the above technical solution, the positive correction component 131 includes multiple sets of wide springs 1311. The multiple sets of wide springs 1311 are arranged at equal intervals along the through groove 20. The bottom side of the through groove 20 is provided with a stepped surface 201 for installing the wide springs 1311. The bottom end of the wide springs 1311 is installed and fixed by bolts corresponding to the screw holes on the stepped surface 201.

[0042] Furthermore, in the above technical solution, the lateral correction component 132 is a set of narrow springs, which are disposed at the top of the guide rail 14 near the inclined guide section 1121.

[0043] Furthermore, in the above technical solution, the side wall of the sorting component 11 near the placement section 1122 is fixedly installed to the T-shaped frame 18 by bolts. The T-shaped frame 18 is provided with guide protrusions that are adapted to the guide rail 14. On the other side of the sorting component 11, the opposite side wall is provided with multiple sets of circular limiting guide blocks corresponding to the guide rail 14. The limiting guide blocks are fixedly installed to the side wall of the sorting component 11 by bolts.

[0044] Furthermore, in the above technical solution, the top outer edge of the feeding component 10 is provided with a folded edge 21, and a screw hole is provided on the folded edge 21. During installation, the feeding component 10 is installed and fixed by corresponding the screw hole on the folded edge to the mounting hole on the equipment. At this time, the top of the feeding component 10 is closed, and only the sample outlet is left on the side close to the sorting component 11. The anti-jamming mechanism 13 is used to prevent the sample outlet from jamming.

[0045] Furthermore, in the above technical solution, the contact surface of the wide spring 1311 is an inclined plane. When interference sample tubes are piled up above the sorting component 11, lateral pressure can be applied sequentially through the contact surface of the wide spring 1311 to make them fall from above and prevent tube jamming. The contact surface of the lateral correction component 132 is an arc-shaped surface, which is used to prevent the inclined guide section 1121 at the high position from jamming the tube at the contact position with the first set of wide springs 1311.

[0046] Furthermore, in the above technical solution, a machine compartment is provided on one side of the unloading component 10, and an electric push rod is installed in the machine compartment to drive the opening and closing of the compartment cover 19.

[0047] Specifically, the principle of this invention is as follows: The operator opens the hopper cover and feeds a batch of sample tubes into the feeding component. Under the action of gravity, the sample tubes slide along the guide slope into the channel. At this time, the sorting component is in a low position inside the channel. During the process of the drive motor driving the sorting component to rise, multiple sample tubes fall into the sorting chamber under the action of gravity. Since the diameter of the tube cap is larger than the tube clearance, it rolls and deflects during the falling process, keeping the sample tube in a normal posture (i.e., the tube cap is facing upwards, and the tube body is vertical in the sorting chamber). The first sample tube is in the placement section position. At this time, if any sample tube gets stuck in the movement range of the sorting component (such as being horizontally placed above multiple sample tubes), the sorting component will lift the stuck tube during its rising process. When it reaches the forward correction component, multiple sets of wide springs apply a combined lateral and downward pressure to the stuck tube through the oblique contact surface, causing it to get out of the stuck state and fall into the sorting chamber or return to the hopper. If the stuck tube position is close to the junction of the inclined guide section and the guide rail, it is pushed away from the stuck corner position by the arc-shaped contact surface of the top narrow spring, while avoiding the movement of the sorting component and preventing stroke interference.

[0048] The superiority of this solution lies in its ability to quickly reposition disordered sample tubes (vertical tubes) through the vertical reciprocating motion of the sorting component, ensuring that the tubes are in a position at the sample outlet that allows them to be grasped by the mechanical grippers. Importantly, this solution can output multiple tubes at once. Unlike existing technologies, when there are multiple sample tubes above the tube-sorting step of the sorting component, after each sample tube in the placement section is grasped, the subsequent sample tubes are moved forward to fill the gap due to the influence of the inclined guide section. When facing a high-efficiency processing platform, such as multi-gripper collaborative processing, this solution can greatly improve the efficiency of sample processing.

Claims

1. A sample tube sorting and loading / unloading mechanism, characterized in that, It includes a feeding component (10) and a sorting component (11). The bottom end of the feeding component (10) is provided with a channel (102) for the sorting component (11) to move. An anti-jamming mechanism (13) is provided on the inner wall of the channel (102). Guide rails (14) are provided on both sides of the channel (102). The sorting component (11) makes vertical reciprocating motion through a lifting drive assembly (12).

2. The sample tube sorting and feeding mechanism according to claim 1, characterized in that, The bottom of the feeding component (10) is provided with an inclined guiding slope (101), and the sorting component (11) is provided on the lower side near the guiding slope (101); the sorting component (11) is provided with a hollow sorting cavity (111), the top of the sorting cavity (111) is connected to the outside and the edge is provided with an inclined tube-sorting step surface (112), the higher side of the tube-sorting step surface (112) is an inclined guide section (1121), and the lower side is provided with a placement section (1122); the anti-stuck tube mechanism (13) includes a forward correction component (131) and a lateral correction component (132).

3. The sample tube sorting and feeding mechanism according to claim 2, characterized in that, The tube-cleaning gap (113) of the sorting component (11) is greater than the tube body diameter of the sample tube and less than the tube cap diameter of the sample tube.

4. The sample tube sorting and feeding mechanism according to claim 3, characterized in that, The lifting drive assembly (12) includes a drive motor (121), a linear guide rail (122), and a trolley (123). The drive motor (121) is fixedly mounted on the top of the linear guide rail (122), and its output end is connected to the drive wheel (15). Through the transmission belt (17) and the driven wheel (16) at the bottom of the linear guide rail (122), the trolley (123) is driven to reciprocate up and down along the linear guide rail (122). The trolley (123) is fixedly mounted to one side of the sorting component (11) through a T-shaped frame (18).

5. The sample tube sorting and feeding mechanism according to claim 4, characterized in that, The feeding component (10) is a sample tube feeding bin with storage space, and a bin cover (19) is movably provided on one side of the outer end. The other end of the feeding component (10) relative to the bin cover (19) is close to the inner wall of the sorting component (11) and has a through groove (20) for accommodating and installing the positive correction component (131).

6. The sample tube sorting and feeding mechanism according to claim 5, characterized in that, The positive correction component (131) includes multiple sets of wide springs (1311), which are equally spaced along the through groove (20). The bottom side of the through groove (20) is provided with a stepped surface (201) for installing the wide springs (1311). The bottom end of the wide springs (1311) is fixed by bolts corresponding to the screw holes on the stepped surface (201).

7. A sample tube sorting and feeding mechanism according to claim 6, characterized in that, The lateral correction component (132) is a set of narrow springs, which are disposed at the top of the guide rail (14) on the side near the inclined guide section (1121).

8. The sample tube sorting and feeding mechanism according to claim 7, characterized in that, The sorting component (11) is fixedly installed to the T-shaped frame (18) near the side wall of the placement section (1122) by bolts. The T-shaped frame (18) is provided with guide protrusions adapted to the guide rail (14). On the other side of the sorting component (11), opposite to the guide rail (14), multiple sets of circular limiting guide blocks are provided. The limiting guide blocks are fixedly installed to the side wall of the sorting component (11) by bolts.

9. A sample tube sorting and feeding mechanism according to claim 8, characterized in that, The top outer edge of the feeding component (10) is provided with a folded edge (21), and a screw hole is provided on the folded edge (21). During installation, the screw hole on the folded edge is used to install and fix the component by corresponding to the mounting hole on the device. At this time, the top of the feeding component (10) is closed, and only the sample outlet is left on the side close to the sorting component (11). The anti-jamming mechanism (13) is used to prevent the sample outlet from jamming.

10. A sample tube sorting and feeding mechanism according to claim 9, characterized in that, The contact surface of the wide spring sheet (1311) is an inclined plane. When interference sample tubes are piled up above the sorting component (11), lateral pressure can be applied sequentially through the contact surface of the wide spring sheet (1311) to make them fall from above and prevent the tube from getting stuck. The contact surface of the lateral correction component (132) is an arc-shaped surface, which is used to prevent the inclined guide section (1121) at the high position from getting stuck at the contact position with the first set of wide spring sheets (1311).

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