Variable-pitch pipetting arm

Abstract

The utility model relates to the technical field of pipetting equipment, and discloses a variable-pitch pipetting arm which comprises a variable-pitch assembly and a power assembly, according to the variable-pitch pipetting arm disclosed by the utility model, when the variable-pitch pipetting arm is applied to a pipetting row, all pipetting parts in the pipetting row are respectively connected to different first hinge points in the variable-pitch assembly, so that the whole pipetting row can move along a first direction through the matching of the variable-pitch assembly and the power assembly; or the distance between two adjacent pipetting parts in the pipetting row is changed.

Description

Technical Field

[0001] This utility model relates to the field of pipetting equipment technology, and more specifically, to a variable-pitch pipetting arm. Background Technology

[0002] The content in this section only provides background information related to this utility model and may not constitute prior art.

[0003] In pipetting equipment that uses pipetting components such as pipettes for pipetting, multiple pipetting components are usually arranged side by side to form a pipetting array, so as to transfer more liquid in a single operation and thus improve pipetting efficiency.

[0004] In addition, in practical applications, the size and specifications of devices used for temporary storage of liquids to be transferred vary, so that under different operating conditions, there may be a need to change the spacing between two adjacent pipetting components in the pipetting array. Furthermore, in order to transfer the liquid, the pipetting array should at least have the ability to move as a whole. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a variable pitch pipette arm that can change the distance between two adjacent pipette parts in a pipette array and allow the entire pipette array to move.

[0006] The objective of this utility model is achieved through the following technical solution:

[0007] This utility model discloses a variable-pipette arm, comprising:

[0008] A pitch-adjustable assembly includes multiple link units arranged sequentially along a first direction; each link unit includes a first link and a second link, which are hinged to form a first hinge point; in two adjacent link units, the first link of one link unit and the second link of the other link unit, as well as the second link of one link unit and the first link of the other link unit, are hinged to form a second hinge point;

[0009] The power assembly includes a first movable member and a second movable member that can move along a first direction;

[0010] Two adjacent linkage units in a plurality of linkage units are defined as a linkage unit group; the first moving member is movably connected to two second hinge points in one of the linkage unit groups, such that the two second hinge points in the linkage unit group can move relative to the first moving member along a second direction; the second moving member is movably connected to two second hinge points in another linkage unit group, such that the two second hinge points in the linkage unit group can move relative to the second moving member along a second direction; the second direction is perpendicular to the first direction.

[0011] Furthermore, the first moving member is provided with a first sliding groove that cooperates with the corresponding second hinge point and extends along the second direction, and a first sliding part is provided at the second hinge point corresponding to the first moving member, and the first sliding part is slidably disposed in the corresponding first sliding groove;

[0012] The second moving member is provided with a second sliding groove that cooperates with the corresponding second hinge point and extends along the second direction. A second sliding part is provided at the second hinge point corresponding to the second moving member, and the second sliding part is slidably disposed in the corresponding second sliding groove.

[0013] Furthermore, the variable-pipette arm also includes a frame;

[0014] Both the first and second movable components are slidably connected to the frame, enabling both the first and second movable components to move along the first direction in a sliding manner.

[0015] Furthermore, a pitch-changing component is connected at the first hinge point, and the pitch-changing component is slidably connected to the frame so that the pitch-changing component can slide along the first direction.

[0016] Furthermore, the frame is provided with a slide rail extending along the first direction, and the slide rail is provided with a slider that can slide along the slide rail and is connected to the corresponding pitch changer.

[0017] The sliders corresponding to the two adjacent pitch-changing elements are offset in the second direction.

[0018] Furthermore, the pitch control assembly and the power assembly are distributed on opposite sides of the frame, and the frame is provided with a clearance extending along the first direction.

[0019] Furthermore, the power assembly also includes a first drive unit and a second drive unit;

[0020] Both the first driving unit and the second driving unit are adapted to output reciprocating linear motion along the first direction. The output end of the first driving unit is connected to the first moving member, and the output end of the second driving unit is connected to the second moving member.

[0021] Furthermore, the first drive unit includes a first drive motor, a first drive wheel, a first driven wheel, and a first synchronous belt;

[0022] The first driving wheel is connected to the output end of the first drive motor. The first driving wheel and the first driven wheel are arranged sequentially along the first direction. The first synchronous belt connects the first driving wheel and the first driven wheel, and the first synchronous belt is connected to the first moving member.

[0023] Furthermore, the second drive unit includes a second drive motor, a second drive wheel, a second driven wheel, and a second synchronous belt;

[0024] The second driving wheel is connected to the output end of the second drive motor. The second driving wheel and the second driven wheel are arranged sequentially along the first direction. The second synchronous belt connects the second driving wheel and the second driven wheel, and the second synchronous belt is connected to the second moving member.

[0025] Furthermore, the first moving member is movably connected to two second hinge points in the linkage unit group at the center of the pitch-changing assembly, and the second moving member is movably connected to two second hinge points in the linkage unit group at one end of the pitch-changing assembly.

[0026] The technical solution of this utility model embodiment has at least the following advantages and beneficial effects:

[0027] The variable-pitch pipette arm disclosed in this utility model, by setting a variable-pitch assembly including multiple linkage units arranged sequentially along a first direction, and a power assembly including a first moving member and a second moving member that can move along the first direction, when the variable-pitch pipette arm is applied to a pipette assembly, it is only necessary to connect each pipetting component in the pipette assembly to different first hinge points in the variable-pitch assembly. The entire pipette assembly can be moved along the first direction or the distance between two adjacent pipetting components in the pipette assembly can be changed through the cooperation of the variable-pitch assembly and the power assembly. Attached Figure Description

[0028] Figure 1 A schematic diagram of the structure of the variable pitch pipette arm provided for an embodiment of the present invention in one state shows the case where the distance between two adjacent variable pitch components is at its minimum.

[0029] Figure 2A schematic diagram of the structure of the variable pitch component provided in an embodiment of this utility model;

[0030] Figure 3 A schematic diagram of the structure of the first moving member, the second moving member, the pitch-changing assembly, and the slide bar provided for embodiments of this utility model;

[0031] Figure 4 A schematic diagram of the pitch control assembly and pitch control element provided for embodiments of this utility model;

[0032] Figure 5 A schematic diagram of the frame and power assembly provided for an embodiment of the present invention from one view.

[0033] Figure 6 A schematic diagram of the frame and power assembly provided for an embodiment of the present invention from another perspective;

[0034] Figure 7 , Figure 8 and Figure 9 This is a reference diagram showing the usage state of the variable-pipette arm provided in an embodiment of the present invention, wherein... Figure 7 and Figure 8 This illustrates the scenario where multiple pitch-changing components move as a whole along a first direction. Figure 9 This illustrates the situation where the distance between two adjacent pitch elements in a plurality of pitch elements increases.

[0035] Icons: 10-Frame, 11-Allowing opening, 20-Pitch variable assembly, 21-Link unit, 211-First link, 212-Second link, 22-First hinge shaft, 23-Second hinge shaft, 24-First sliding part, 25-Second sliding part, 30-Power assembly, 31-First moving part, 311-First slide groove, 32-Second moving part, 321-Second slide groove, 33-First drive unit, 331-First drive motor, 332-First driving wheel, 333-First driven wheel, 334-First synchronous belt, 34-Second drive unit, 341-Second drive motor, 342-Second driving wheel, 343-Second driven wheel, 344-Second synchronous belt, 40-Slide bar, 50-Slide rail, 60-Slider, 100-Pitch variable assembly. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below in conjunction with specific embodiments. The same reference numerals in the accompanying drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0037] Compared to the embodiments shown in the accompanying drawings, feasible embodiments within the scope of protection of this utility model may have fewer components, have other components not shown in the drawings, different components, components arranged differently, or components with different connections, etc. Furthermore, two or more components shown in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as multiple separate components.

[0038] This invention discloses a variable-pitch pipette arm applicable to pipetting arrays. The pipetting array may include multiple pipetting components arranged sequentially along a first direction; each pipetting component can be a pipette. By applying the variable-pitch pipette arm disclosed in this invention to a pipetting array, at least the distance between two adjacent pipetting components in the pipetting array can be changed, while simultaneously allowing the entire pipetting array to move along the first direction.

[0039] Of course, the variable pitch pipette arm disclosed in this embodiment can also be applied to other components that need to change the pitch and move as a whole. For ease of explanation, the individual components that need to change the pitch in this embodiment are collectively referred to as variable pitch component 100.

[0040] Figure 1 This is a schematic diagram of the structure of an exemplary variable-pitch pipette arm disclosed in one state according to an embodiment of the present invention, showing the case where the distance between two adjacent variable-pitch elements 100 is at its minimum.

[0041] like Figure 1 As shown, the variable-pitch pipette arm disclosed in this embodiment of the present invention may include a frame 10, a variable-pitch assembly 20, and a power assembly 30. The frame 10 mainly provides a carrier for the installation of the power assembly 30 and the variable-pitch component 100. The variable-pitch assembly 20 mainly provides a carrier for the installation of the variable-pitch component 100, and works with the power assembly 30 to change the distance between two adjacent variable-pitch components 100, or works with the power assembly 30 to achieve the overall movement of multiple variable-pitch components 100.

[0042] Figure 2 The general structure of the exemplary pitch component 20 disclosed in this embodiment of the present invention is shown. Figure 2As shown, the pitch control assembly 20 may include a plurality of link units 21 arranged sequentially along a first direction, each link unit 21 including a first link 211 and a second link 212. For example, the accompanying drawings of this utility model show a pitch control assembly 20 with a total of eight link units 21. Of course, the number of link units 21 is not limited to this and may be more or less.

[0043] In this configuration, the first link 211 and the second link 212 of each link unit 21 can be hinged together via a first hinge shaft 22 to form a first hinge point a. At this time, the first hinge points a of the multiple link units 21 are located on the same straight line extending along a first direction.

[0044] In two adjacent linkage units 21, the first link 211 of one linkage unit 21 and the second link 212 of the other linkage unit 21, as well as the second link 212 of one linkage unit 21 and the first link 211 of the other linkage unit 21, can be hinged together by a second hinge shaft 23 to form a second hinge point b. It can be seen that there are two second hinge points b in two adjacent linkage units 21, and the line connecting these two second hinge points b is perpendicular to the line connecting the first hinge points a in the plurality of linkage units 21. That is, the two second hinge points b are located on the same straight line extending along a second direction, which is perpendicular to the first direction.

[0045] It is understood that the variable pitch assembly 20 constructed in the above manner is also a scissor linkage mechanism. Furthermore, the first direction described in this embodiment of the invention can be understood as... Figure 1 The X-axis direction shown in the diagram, the second direction can be understood as... Figure 1 The Y-axis direction is shown in the diagram.

[0046] Figure 5 The general structure of the exemplary frame 10 and power assembly 30 disclosed in this embodiment of the present invention is shown. Figure 5 As shown, the power assembly 30 may include a first movable member 31 and a second movable member 32 that can move along a first direction.

[0047] For example, both the first movable member 31 and the second movable member 32 can be slidably connected to the frame 10, allowing both to move in a sliding manner along the first direction. Alternatively, a slide bar 40 extending along the first direction can be provided on the frame 10, and the slide bar 40 can pass through both the first movable member 31 and the second movable member 32 simultaneously, enabling both to move in a sliding manner along the first direction.

[0048] To improve the stability of the first moving member 31 and the second moving member 32 during movement, multiple slide bars 40 can be provided, and the multiple slide bars 40 can be arranged sequentially along the second direction. For example, Figure 5 The illustrated embodiment shows a configuration with two slide bars 40.

[0049] Furthermore, referring to Figure 3 As shown, assuming that two adjacent link units 21 in a plurality of link units 21 are defined as a group of link units, then: the first moving member 31 is movably connected to two second hinge points b in one of the group of link units, so that the two second hinge points b in the group of link units can move relative to the first moving member 31 in a second direction; correspondingly, the second moving member 32 is movably connected to two second hinge points b in another group of link units, so that the two second hinge points b in the group of link units can move relative to the second moving member 32 in a second direction.

[0050] For example, but not limited to, the movable connection between the first moving member 31 and the corresponding two second hinge points b, and between the second moving member 32 and the corresponding two second hinge points b, can be achieved in the manner described below.

[0051] like Figure 3 As shown, a first sliding groove 311 extending along a second direction and engaging with the corresponding second hinge point b can be provided on the first moving member 31. In this case, a first sliding portion 24 can be provided on the second hinge shaft 23 at the second hinge point b corresponding to the first moving member 31, and the first sliding portion 24 is slidably disposed within the corresponding first sliding groove 311. Thus, the second hinge point b corresponding to the first moving member 31 can move relative to the first moving member 31 along the second direction, and the power generated when the first moving member 31 moves along the first direction can be transmitted to the pitch converter 20.

[0052] Similarly, continue to refer to Figure 3 The second moving member 32 can be provided with a second sliding groove 321 that mates with the corresponding second hinge point b and extends along the second direction. At this time, a second sliding part 25 can be provided on the second hinge shaft 23 at the second hinge point b corresponding to the second moving member 32, and the second sliding part 25 is slidably disposed within the corresponding second sliding groove 321. In this way, the second hinge point b corresponding to the second moving member 32 can move relative to the second moving member 32 along the second direction, and the power of the second moving member 32 moving along the first direction can be transmitted to the pitch converter 20.

[0053] The first moving member 31 can be movably connected to two second hinge points b in the linkage unit group at the center of the pitch assembly 20, and the second moving member 32 can be movably connected to two second hinge points b in the linkage unit group at one end of the pitch assembly 20, so as to realize reliable power transmission.

[0054] Based on this, combined Figure 1 and Figure 4 As shown, by simply installing a pitch reducer 100 at the first hinge point a in each linkage unit 21, the distance between two adjacent pitch reducers 100 can be changed through the cooperation of the power assembly 30 and the pitch reducer assembly 20, or multiple pitch reducers 100 can be moved synchronously along the first direction. The pitch reducer 100 corresponding to the first hinge point a can be connected to the first hinge shaft 22 at the first hinge point a.

[0055] Specifically, the working principle of the variable-pipette arm disclosed in this embodiment of the present invention is roughly as follows:

[0056] If the first moving member 31 and the second moving member 32 move at the same speed in the same direction along the first direction, then refer to Figure 7 and Figure 8 During the change process shown, the entire pitch component 20 will not expand or contract, but will move synchronously with the first moving member 31 and the second moving member 32, thereby achieving the purpose of making multiple pitch components 100 move synchronously along the first direction.

[0057] Conversely, refer to Figure 9 As shown, if there is a speed difference between the movement of the first moving member 31 and the second moving member 32 in the first direction, the pitch-changing assembly 20 will expand or contract accordingly, and the distance between two adjacent first hinge points a in the pitch-changing assembly 20 will change, thereby achieving the purpose of changing the distance between two adjacent pitch-changing members 100.

[0058] The speed difference between the first moving member 31 and the second moving member 32 in the first direction includes at least the following situations: 1. The first moving member 31 is stationary, and the second moving member 32 moves towards or away from the first moving member 31 at any speed along the first direction; 2. The second moving member 32 is stationary, and the first moving member 31 moves towards or away from the second moving member 32 at any speed along the first direction; 3. The first moving member 31 and the second moving member 32 move towards each other at the same or different speeds along the first direction; 4. The first moving member 31 and the second moving member 32 move away from each other at the same or different speeds along the first direction; 5. The first moving member 31 and the second moving member 32 move in the same direction along the first direction at different speeds.

[0059] It is worth noting that in the above situations, there will be a speed difference in the movement of the first moving member 31 and the second moving member 32 in the first direction. Based on this, the pitch component 20 will expand or contract accordingly, thereby changing the distance between two adjacent pitch components 100 connected to each first hinge point a, and the distance between each two adjacent pitch components 100 changes approximately synchronously.

[0060] Alternatively, the pitch reducer 100 connected to the first hinge point a can be configured to move along a first direction to improve the stability of the pitch reducer 100 when moving along the first direction. Specifically, the pitch reducer 100 can be slidably connected to the frame 10, allowing the pitch reducer 100 to move slidably along the first direction. For example, refer to... Figure 6 As shown, a sliding connection between the pitch member 100 and the frame 10 can be achieved by setting a slide rail 50 extending along a first direction on the frame 10, and setting a slider 60 on the slide rail 50 that can slide along the slide rail 50 and connect to the corresponding pitch member 100.

[0061] There can be multiple sliders 60 connected to each pitch-changing member 100, such as two, and these sliders 60 can be arranged sequentially along the second direction to further improve the stability of the pitch-changing member 100 when it moves along the first direction. Furthermore, the positions of the sliders 60 corresponding to two adjacent pitch-changing members 100 in the second direction can be staggered, which helps to reduce the minimum distance between two adjacent pitch-changing members 100.

[0062] It is worth noting that, in actual implementation, a pitch reducer 100 can be provided at each of the first hinge points a in the pitch reducer assembly 20. Of course, a pitch reducer 100 can also be provided only at some of the first hinge points a. For example, two adjacent pitch reducers 100 can be provided at intervals of one or more first hinge points a, which is not limited here.

[0063] In some embodiments of this utility model, in order to enable the first moving member 31 and the second moving member 32 to move independently along the first direction, refer to Figure 5 As shown, the power assembly 30 may also include a first drive unit 33 and a second drive unit 34.

[0064] Both the first drive unit 33 and the second drive unit 34 are adapted to output reciprocating linear motion along a first direction. The output end of the first drive unit 33 is connected to the first moving member 31, and the output end of the second drive unit 34 is connected to the second moving member 32. In this way, the first drive unit 33 can be used to drive the first moving member 31 to move along the first direction, and the second drive unit 34 can be used to drive the second moving member 32 to move along the first direction.

[0065] The first drive unit 33 and the second drive unit 34 can have the same or different structures, as long as they can output reciprocating linear motion along the first direction. For example, both the first drive unit 33 and the second drive unit 34 can be conventional linear actuators such as electric actuators or cylinders.

[0066] Of course, the first drive unit 33 and the second drive unit 34 can also have the same structure as described below, which is conducive to more precise control of the moving speed of the first moving member 31 and the second moving member 32, while minimizing costs.

[0067] Reference Figure 5 As shown, the first drive unit 33 and the second drive unit 34 have essentially the same structure. The first drive unit 33 may include a first drive motor 331, a first driving wheel 332, a first driven wheel 333, and a first synchronous belt 334. The first drive motor 331 may be fixedly mounted on the frame 10, and the first driving wheel 332 is drivenly connected to the output end of the first drive motor 331.

[0068] The first driven wheel 333 is rotatably mounted on the frame 10, and the first driving wheel 332 and the first driven wheel 333 are arranged sequentially along the first direction. The first synchronous belt 334 connects the first driving wheel 332 and the first driven wheel 333, and the first synchronous belt 334 is also connected to the first moving member 31.

[0069] Thus, when the first drive motor 331 operates to make the first synchronous belt 334 move around the first driving pulley 332 and the first driven pulley 333, the first synchronous belt 334 can drive the first moving member 31 to move along the first direction.

[0070] Continue to refer to Figure 5 The second drive unit 34 may include a second drive motor 341, a second drive wheel 342, a second driven wheel 343, and a second synchronous belt 344. The second drive motor 341 may be fixedly mounted on the frame 10, and the second drive wheel 342 is drivenly connected to the output end of the second drive motor 341.

[0071] The second driven wheel 343 is rotatably mounted on the frame 10, and the second driving wheel 342 and the second driven wheel 343 are arranged sequentially along the first direction. The second synchronous belt 344 connects the second driving wheel 342 and the second driven wheel 343, and the second synchronous belt 344 is also connected to the second moving member 32.

[0072] Thus, referring to the operating principle of the first drive unit 33, when the second drive motor 341 is working, the second synchronous belt 344 will drive the second moving part 32 to move along the first direction.

[0073] The first drive motor 331 and the second drive motor 341 can be located at the same end of the frame 10, and they can be opposite each other; the first driven wheel 333 and the second driven wheel 343 can be located at the other end of the frame 10, and they can also be opposite each other. This helps to optimize the structural design of the entire variable pitch pipette arm and minimize its size.

[0074] In some embodiments of this utility model, reference is made to Figure 1 and Figure 5 As shown, the pitch control assembly 20 and the power assembly 30 can be distributed on opposite sides of the frame 10. The frame 10 is provided with a clearance opening 11 extending along a first direction. This clearance opening 11 is mainly used to allow the first moving part 31 and the second moving part 32 in the power assembly 30 to smoothly connect with the corresponding second hinge point b in the pitch control assembly 20. This layout design helps to improve the compactness and aesthetics of the entire pitch control pipetting arm structure.

[0075] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A variable-length pipetting arm, characterized by, The variable distance assembly comprises a plurality of linkage units arranged in sequence along a first direction; each linkage unit comprises a first linkage and a second linkage, and the first linkage and the second linkage are hingedly connected to form a first hinged joint; in two adjacent linkage units, the first linkage of one linkage unit and the second linkage of the other linkage unit are hingedly connected to form a second hinged joint, and the second linkage of the one linkage unit and the first linkage of the other linkage unit are hingedly connected to form a second hinged joint; The power assembly comprises a first moving part and a second moving part which are movable along the first direction; Two adjacent linkage units in the plurality of linkage units are defined as a linkage unit group; the first moving part is movably connected to two second hinged joints in one linkage unit group, so that the two second hinged joints in the linkage unit group can move along a second direction relative to the first moving part; the second moving part is movably connected to two second hinged joints in another linkage unit group, so that the two second hinged joints in the linkage unit group can move along the second direction relative to the second moving part; the second direction is perpendicular to the first direction. The first moving part is provided with a first sliding groove matched with the corresponding second hinged joint and extending along the second direction, and the second hinged joint corresponding to the first moving part is provided with a first sliding part slidably arranged in the corresponding first sliding groove; 2. The variable distance pipetting arm of claim 1, wherein, The second moving part is provided with a second sliding groove matched with the corresponding second hinged joint and extending along the second direction, and the second hinged joint corresponding to the second moving part is provided with a second sliding part slidably arranged in the corresponding second sliding groove. The frame is further provided; 3. The variable distance pipetting arm of claim 1, wherein, The first moving part and the second moving part are both slidably connected to the frame, so that the first moving part and the second moving part can move along the first direction in a sliding manner. The first hinged joint is connected with a variable distance part, and the variable distance part is slidably connected to the frame, so that the variable distance part can move along the first direction in a sliding manner.

4. The variable distance pipetting arm of claim 3, wherein, The frame is provided with a sliding rail extending along the first direction, and the sliding rail is provided with a sliding block slidably arranged on the sliding rail and connected to the corresponding variable distance part; 5. The variable distance pipetting arm of claim 4, wherein, The sliding blocks corresponding to the adjacent two variable distance parts are staggered in the second direction. The variable distance assembly and the power assembly are distributed on opposite sides of the frame, and the frame is provided with an avoiding opening extending along the first direction.

6. The variable distance pipetting arm of claim 3, wherein, The power assembly further comprises a first driving unit and a second driving unit; 7. The variable distance pipetting arm of claim 1, wherein, The first driving unit and the second driving unit are both adapted to output reciprocating linear motion along the first direction, the output end of the first driving unit is connected to the first moving part, and the output end of the second driving unit is connected to the second moving part. The first driving unit comprises a first driving motor, a first driving wheel, a first driven wheel and a first synchronous belt.

8. The variable-volume pipetting arm of claim 7, wherein, ​ The first driving motor is connected to the first driving unit, the first driving motor is connected to the output end of the first driving motor, the first driving motor and the first driven wheel are arranged in sequence along the first direction, the first synchronous belt is connected to the first driving motor and the first driven wheel, and the first synchronous belt is connected to the first moving part.

9. The variable-volume pipetting arm of claim 7, wherein, The second driving unit comprises a second driving motor, a second driving wheel, a second driven wheel and a second synchronous belt. The second driving motor is connected to the output end of the second driving motor, the second driving motor and the second driven wheel are arranged in sequence along the first direction, the second synchronous belt is connected to the second driving motor and the second driven wheel, and the second synchronous belt is connected to the second moving part.

10. The variable distance pipetting arm of claim 1, wherein, The first moving part is movably connected to two second hinge points in the connecting rod unit group at the center of the variable distance assembly, and the second moving part is movably connected to two second hinge points in the connecting rod unit group at one end of the variable distance assembly.

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