A neurosurgical surgical puncture localizer

Abstract

The application discloses a neurosurgery puncture positioner and relates to the technical field of puncture positioners, which comprises a bed body, a C-shaped track frame and a mechanical arm. The mechanical arm comprises a mounting head, and a guide sleeve is detachably connected to the mounting head. The top of the mounting head is connected with a lifting block through a guide mechanism, and the top of the lifting block is connected with a pushing block through a first spring telescopic rod. The neurosurgery puncture positioner can keep the puncture action stable under the condition of unstable artificial pushing force, reduce the influence of unstable artificial pushing force, guarantee the puncture effect, avoid the rotation of the puncture needle during puncture, guarantee the puncture effect, and limit the position when the puncture needle hits the bone, calcification focus or dense fibrosis tissue. The neurosurgery puncture positioner can not only avoid the damage of the puncture needle, but also remind the operator to change the puncture position.

Description

Technical Field

[0001] This invention relates to the field of puncture positioning technology, specifically a neurosurgical puncture positioning device. Background Technology

[0002] Neurosurgical puncture surgery, as a core minimally invasive technique for treating diseases such as intracranial tumor biopsy, hematoma evacuation, and deep brain stimulation electrode implantation, relies heavily on the precision of puncture localization for its safety and therapeutic effect. It requires accurately reaching the target lesion while minimizing the obstruction of critical anatomical structures such as intracranial blood vessels and nerve fiber bundles. Currently, a puncture surgery navigation and positioning system is primarily used, consisting of a bed, a C-shaped track frame, and a robotic arm. The equipment uses the C-shaped track frame as its basic support structure, combined with the robotic arm to flexibly adapt the puncture position and angle. The C-shaped track frame provides an arc-shaped motion trajectory, and the robotic arm can translate and rotate along the track to adjust and position the installation head. After adjustment, the operator first installs the guide sleeve on the installation head, then manually inserts the puncture needle into the guide sleeve and performs the puncture operation, covering puncture target points in different areas of the intracranial cavity.

[0003] However, existing neurosurgical puncture locators require the operator to advance the puncture needle, which can easily lead to unstable punctures due to unstable manual pushing force, affecting the puncture effect. At the same time, the puncture needle is prone to rotation during puncture, which also affects the puncture effect. Furthermore, when the puncture needle encounters bone, calcifications, or dense fibrous tissue, it is not easy to detect in time. Continuing to insert it can easily cause damage to the puncture needle, which will also affect the puncture effect.

[0004] Therefore, we propose a neurosurgical puncture locator. Summary of the Invention

[0005] The purpose of this invention is to provide a neurosurgical puncture locator to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a neurosurgical puncture locator, comprising a bed, a C-shaped track frame, and a robotic arm. The robotic arm includes a mounting head, and a guide sleeve is detachably connected to the mounting head. A lifting block is connected to the top of the mounting head via a guide mechanism, and a pushing block is connected to the top of the lifting block via a first spring telescopic rod. A pushing rod is fixedly connected to the side wall of the pushing block, and a friction mechanism is provided on the top of the pushing block to provide frictional resistance to the movement of the pushing block. A clamping mechanism is provided on the side wall of the lifting block to clamp and limit the puncture needle, and a limiting mechanism is provided between the pushing block and the lifting block to limit the movement of the pushing block.

[0007] Preferably, the friction mechanism includes a fixed plate fixedly connected to the side wall of the mounting head, and a first moving block is connected to the top of the pushing block through a first moving mechanism. A rubber wheel is rotatably connected to the side wall of the first moving block through a rotating mechanism, and the rubber wheel abuts against the fixed plate.

[0008] By adopting the above technical solution, the first moving mechanism drives the first moving block to move, and at the same time, the rotating mechanism drives the rubber wheel to move. When the rubber wheel abuts against the side wall of the fixed plate, the rubber wheel can be squeezed and deformed, and when the pushing block moves downward, it can provide resistance.

[0009] Preferably, the first moving mechanism includes a fixed block fixedly connected to the top of the push block, and a threaded rod rotatably connected to the side wall of the fixed block. A threaded tube is threadedly connected to the side wall of the threaded rod, and the other end of the threaded tube is fixed to the side wall of the first moving block. A first rocker wheel is fixedly connected to one end of the threaded rod, and a guide assembly is provided between the fixed block and the first moving block.

[0010] By adopting the above technical solution, the first rocker wheel is rotated, and the rotation of the first rocker wheel drives the rotation of the threaded rod, thereby enabling the first moving block to move through the threaded tube, and at the same time, it is guided by the guide assembly.

[0011] Preferably, the guiding assembly includes two first guide rods fixedly connected to the side wall of the fixed block, and each first guide rod has a first guide tube sleeved on its side wall. The other end of the first guide tube is fixed to the side wall of the first moving block, and the side wall of the first guide rod is provided with scale markings.

[0012] By adopting the above technical solution, when the first moving block moves, the first guide tube slides on the side wall of the first guide rod. By observing the scale markings, the squeezing pressure between the rubber wheel and the fixed plate can be controlled.

[0013] Preferably, the rotating mechanism includes two mounting blocks fixedly connected to the side wall of the first moving block, and the rubber wheel is rotatably connected to the side wall of the mounting block through a rotating shaft.

[0014] By adopting the above technical solution, it is ensured that the rubber wheel can rotate along the shaft.

[0015] Preferably, the guiding mechanism includes two second guide tubes fixedly connected to the top of the mounting head, and a second guide rod is inserted into each second guide tube, with the upper end of the second guide rod fixed to the bottom of the lifting block.

[0016] By adopting the above technical solution, when the lifting block moves, the second guide rod moves inside the second guide tube, which can guide the lifting of the lifting block.

[0017] Preferably, the clamping mechanism includes a U-shaped plate fixedly connected to the side wall of the lifting block, and the side wall of the U-shaped plate is connected to two moving plates through a second moving mechanism. The opposite side walls of the two moving plates are connected to two symmetrically arranged V-shaped blocks through a second spring telescopic rod.

[0018] By adopting the above technical solution, the handle of the puncture needle is placed between two V-shaped blocks. At the same time, the second moving mechanism drives the two moving plates to move closer to each other, and the second spring telescopic rod drives the two V-shaped blocks to move closer to each other. When the V-shaped blocks abut against the handle of the puncture needle, the puncture needle can be clamped and limited. Meanwhile, the second spring telescopic rod is gradually compressed, which can prevent the puncture needle from rotating during puncture and ensure the puncture effect.

[0019] Preferably, the second moving mechanism includes two fixed rods fixedly connected to the side wall of the U-shaped plate, and two moving plates sleeved on the side wall of the fixed rods. The side wall of the U-shaped plate is rotatably connected to a double-ended lead screw, and the moving plates are threadedly connected to the threaded part of the double-ended lead screw. One end of the double-ended lead screw is fixedly connected to a second rocker wheel.

[0020] By adopting the above technical solution, rotating the second rocker wheel causes the double-ended lead screw to rotate, thereby driving the two moving plates to move closer to each other along the fixed rod.

[0021] Preferably, the limiting mechanism includes a plurality of limiting holes arranged in an array on the side wall of the fixed plate, and a second moving block is connected between the lifting block and the pushing block through a moving component. A conical block is fixedly connected to the side wall of the second moving block, and the conical block can be inserted into the limiting hole.

[0022] By adopting the above technical solution, when the puncture needle encounters bone, calcification, or dense fibrotic tissue, it will be significantly obstructed. When the pusher pushes the push block to continue moving downwards, the first spring telescopic rod will deform. At the same time, the moving component will drive the second moving block to move closer to the fixed plate. When the second moving block moves, it can drive the conical block to move and insert into the limiting hole for limiting. This not only avoids damage to the puncture needle, but also alerts the operator to change the puncture position.

[0023] Preferably, the moving component includes a first link rotatably connected between the pushing block and the second moving block, and a second link rotatably connected between the lifting block and the second moving block.

[0024] By adopting the above technical solution, when the first spring telescopic rod is compressed, the first connecting rod and the second connecting rod rotate, and drive the second moving block to move closer to the fixed plate.

[0025] In summary: Advantage 1: During puncture, the damping effect of the friction mechanism can maintain a smooth puncture action even when the human thrust is unstable, reducing the impact of unstable human thrust and ensuring the effectiveness of the puncture. Advantage 2: It avoids the needle from rotating during puncture, ensuring the effectiveness of the puncture. Advantage 3: When the puncture needle encounters bone, calcification, or dense fibrotic tissue, it can be stopped, which not only avoids damage to the puncture needle, but also alerts the operator to change the puncture position. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the robotic arm in this invention; Figure 3 This is a schematic diagram showing the positional relationship between the friction mechanism, clamping mechanism, and limiting mechanism in this invention; Figure 4 This is a schematic diagram showing the usage state of the clamping mechanism in this invention; Figure 5 This is a schematic diagram of the clamping mechanism in this invention; Figure 6 This is a schematic diagram of the friction mechanism and the limiting mechanism in this invention; Figure 7 This is a schematic diagram of the limiting mechanism in this invention; Figure 8 This is a schematic diagram of the friction mechanism in this invention.

[0027] In the diagram: 101, Bed frame; 102, C-shaped track frame; 103, Robotic arm; 104, Mounting head; 105, Guide sleeve; 201, Fixing plate; 202, First moving block; 203, Rubber wheel; 301, Fixing block; 302, Threaded tube; 303, Threaded rod; 304, First rocker wheel; 401, First guide tube; 402, First guide rod; 403, Scale markings; 501, Second guide tube; 502, Second guide rod; 601, U 602. Profile plate; 603. Moving plate; 604. Second spring telescopic rod; 705. V-block; 706. Fixed rod; 707. Double-ended lead screw; 708. Second rocker wheel; 809. Limiting hole; 800. Second moving block; 801. Conical block; 902. Second connecting rod; 1001. Mounting block; 1002. Rotating shaft; 11. Puncture needle; 12. Lifting block; 13. First spring telescopic rod; 14. Push rod; 15. Push block. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0029] Please see Figures 1-8 The illustration shows a neurosurgical puncture locator, including a bed 101, a C-shaped track frame 102, and a robotic arm 103. The robotic arm 103 includes a mounting head 104, on which a guide sleeve 105 is detachably connected. It also includes a preoperative path planning module: based on the patient's intracranial CT / MRI image data, it constructs a three-dimensional anatomical model, automatically identifies lesion target points and key avoidance structures (blood vessels, nerves), generates the optimal puncture path, and outputs the robotic arm 103's posture parameters and puncture depth threshold, providing data support for hardware positioning. These are all well-known technologies in this field and will not be elaborated upon here. A lifting block 12 is connected to the top of the mounting head 104 via a guide mechanism, and a pushing block 15 is connected to the top of the lifting block 12 via a first spring telescopic rod 13. A pushing rod 14 is fixedly connected to the side wall of the pushing block 15. The top of the device is provided with a friction mechanism to provide frictional resistance to the movement of the push block 15. The side wall of the lifting block 12 is provided with a clamping mechanism to clamp and limit the movement of the puncture needle 11. A limiting mechanism is provided between the push block 15 and the lifting block 12 to limit the movement of the push block 15. During puncture, under the damping action of the friction mechanism, the puncture action can be kept stable even when the manual pushing force is unstable. This can prevent the needle from going out of control due to "excessive force" during manual puncture, reduce the impact of unstable manual pushing force, and ensure the puncture effect. At the same time, it can prevent the puncture needle 11 from rotating during puncture, ensuring the puncture effect. Furthermore, when the puncture needle 11 encounters bone, calcification, or dense fibrotic tissue, it can be limited, which can not only prevent damage to the puncture needle 11, but also remind the operator to change the puncture position.

[0030] The friction mechanism includes a fixed plate 201 fixedly connected to the side wall of the mounting head 104, and a first moving block 202 connected to the top of the pushing block 15 via a first moving mechanism. A rubber wheel 203 is rotatably connected to the side wall of the first moving block 202 via a rotating mechanism, and the rubber wheel 203 abuts against the fixed plate 201. The first moving mechanism drives the first moving block 202 to move, and at the same time, the rotating mechanism drives the rubber wheel 203 to move. When the rubber wheel 203 abuts against the side wall of the fixed plate 201, the rubber wheel 203 can be squeezed and deformed, and when the pushing block 15 moves downward, it can provide frictional resistance.

[0031] The first moving mechanism includes a fixed block 301 fixedly connected to the top of the push block 15, and a threaded rod 303 rotatably connected to the side wall of the fixed block 301. A threaded tube 302 is threadedly connected to the side wall of the threaded rod 303, and the other end of the threaded tube 302 is fixed to the side wall of the first moving block 202. A first rocker wheel 304 is fixedly connected to one end of the threaded rod 303, and a guide assembly is provided between the fixed block 301 and the first moving block 202. When the first rocker wheel 304 is rotated, the rotation of the first rocker wheel 304 drives the rotation of the threaded rod 303, thereby enabling the first moving block 202 to move through the threaded tube 302. At the same time, the guide assembly provides guidance.

[0032] The guiding assembly includes two first guide rods 402 fixedly connected to the side wall of the fixed block 301, and a first guide tube 401 is sleeved on the side wall of each first guide rod 402. The other end of the first guide tube 401 is fixed to the side wall of the first moving block 202, and a scale mark 403 is provided on the side wall of the first guide rod 402. When the first moving block 202 moves, the first guide tube 401 slides on the side wall of the first guide rod 402. By observing the scale mark 403, the squeezing pressure between the rubber wheel 203 and the fixed plate 201 can be controlled, and the friction resistance of the friction mechanism can be adjusted and controlled.

[0033] The rotating mechanism includes two mounting blocks 1001 fixedly connected to the side wall of the first moving block 202, and the rubber wheel 203 is rotatably connected to the side wall of the mounting block 1001 through the rotating shaft 1002, so as to ensure that the rubber wheel 203 can rotate along the rotating shaft 1002.

[0034] The guiding mechanism includes two second guide tubes 501 fixedly connected to the top of the mounting head 104, and a second guide rod 502 is inserted into each second guide tube 501. The upper end of the second guide rod 502 is fixed to the bottom of the lifting block 12. When the lifting block 12 moves, the second guide rod 502 moves in the second guide tube 501, which can guide the lifting of the lifting block 12.

[0035] The clamping mechanism includes a U-shaped plate 601 fixedly connected to the side wall of the lifting block 12. The side wall of the U-shaped plate 601 is connected to two moving plates 602 through a second moving mechanism. The opposite side walls of the two moving plates 602 are connected to two symmetrically arranged V-shaped blocks 604 through a second spring telescopic rod 603. The handle of the puncture needle 11 is placed between the two V-shaped blocks 604. At the same time, the second moving mechanism drives the two moving plates 602 to move closer to each other, and the second spring telescopic rod 603 drives the two V-shaped blocks 604 to move closer to each other. When the V-shaped blocks 604 abut against the handle of the puncture needle 11, the puncture needle 11 can be clamped and limited. Meanwhile, the second spring telescopic rod 603 is gradually compressed, which can prevent the puncture needle 11 from rotating during puncture and ensure the puncture effect.

[0036] The second moving mechanism includes two fixed rods 701 fixedly connected to the side wall of the U-shaped plate 601, and two moving plates 602 sleeved on the side wall of the fixed rods 701. A double-ended lead screw 702 is rotatably connected to the side wall of the U-shaped plate 601, and the moving plates 602 are threadedly connected to the threaded part of the double-ended lead screw 702. A second rocker wheel 703 is fixedly connected to one end of the double-ended lead screw 702. Rotating the second rocker wheel 703 causes the double-ended lead screw 702 to rotate, thereby driving the two moving plates 602 to move closer to each other along the fixed rods 701.

[0037] The limiting mechanism includes multiple arrayed limiting holes 801 on the side wall of the fixed plate 201, and a second moving block 802 is connected between the lifting block 12 and the pushing block 15 via a moving component. A conical block 803 is fixedly connected to the side wall of the second moving block 802, and the conical block 803 can be inserted into the limiting hole 801. When the puncture needle 11 encounters bone, calcification, or dense fibrotic tissue, it will be significantly obstructed. When the pushing block 15 is pushed downward by the pushing rod 14, the first spring telescopic rod 13 will deform. At the same time, the moving component will drive the second moving block 802 to move closer to the fixed plate 201. When the second moving block 802 moves, it can drive the conical block 803 to move and insert into the limiting hole 801 for limiting. This not only avoids damage to the puncture needle 11, but also alerts the operator to change the puncture position.

[0038] The moving component includes a first link 901 rotatably connected between the push block 15 and the second moving block 802, and a second link 902 rotatably connected between the lifting block 12 and the second moving block 802. When the first spring telescopic rod 13 is compressed, the first link 901 and the second link 902 rotate, and drive the second moving block 802 to move toward the fixed plate 201.

[0039] Working principle: During use, the C-shaped track frame 102 is moved and adjusted, and the installation head 104 is adjusted by the robotic arm 103, thereby adjusting the puncture position and angle. Then, the guide sleeve 105 is installed on the installation head 104 for guiding.

[0040] Before puncture, the operator tests and adjusts the friction mechanism according to their own situation to find the most comfortable setting. During adjustment, the first rocker wheel 304 is rotated, which drives the threaded rod 303 to rotate, thereby moving the first moving block 202 through the threaded tube 302. At the same time, the first guide tube 401 slides on the side wall of the first guide rod 402. When the rubber wheel 203 abuts against the side wall of the fixed plate 201, the rubber wheel 203 can be squeezed and deformed. By observing the scale markings 403, the squeezing force between the rubber wheel 203 and the fixed plate 201 can be controlled, thereby adjusting and controlling the friction force of the friction mechanism.

[0041] Next, the handle of the puncture needle 11 is placed between the two V-blocks 604. At the same time, the second rocker wheel 703 is rotated. The rotation of the second rocker wheel 703 causes the double-ended lead screw 702 to rotate, thereby driving the two moving plates 602 to move closer to each other along the fixed rod 701. The second spring telescopic rod 603 drives the two V-blocks 604 to move closer to each other. When the V-blocks 604 abut against the handle of the puncture needle 11, the puncture needle 11 can be clamped and limited. At the same time, the second spring telescopic rod 603 is gradually compressed, which can prevent the puncture needle 11 from rotating during puncture and ensure the puncture effect.

[0042] After the clamping limit is completed, the operator holds the push rod 14 and pushes it downward, which can drive the push block 15 to move downward. At the same time, the lifting block 12 is driven to move downward through the first spring telescopic rod 13, and the second guide rod 502 moves downward along the second guide tube 501. Furthermore, the clamping mechanism drives the puncture needle 11 to move downward along the guide sleeve 105 to perform the puncture operation. Meanwhile, the rubber wheel 203 rolls on the side wall of the fixed plate 201. By controlling the squeezing force between the rubber wheel 203 and the fixed plate 201, frictional resistance can be provided when the push block 15 moves downward. Under the damping action of the friction mechanism, the puncture action can be kept stable even when the manual pushing force is unstable. This can prevent the needle from getting out of control due to "excessive force" during manual puncture, reduce the impact of unstable manual pushing force, and ensure the puncture effect.

[0043] When the puncture needle 11 encounters bone, calcification, or dense fibrotic tissue, it will be significantly obstructed. When the pusher block 15 is pushed downward by the pusher rod 14, the first spring telescopic rod 13 is compressed. At the same time, the first connecting rod 901 and the second connecting rod 902 rotate, driving the second moving block 802 to move closer to the fixed plate 201. When the second moving block 802 moves, it can drive the conical block 803 to move and insert into the limiting hole 801 for limiting. This not only avoids damage to the puncture needle 11, but also alerts the operator to change the puncture position.

[0044] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A neurosurgical puncture locator, comprising a bed (101), a C-shaped track frame (102), and a robotic arm (103), wherein the robotic arm (103) includes a mounting head (104), and a guide sleeve (105) is detachably connected to the mounting head (104), characterized in that, The top of the mounting head (104) is connected to a lifting block (12) via a guide mechanism, and the top of the lifting block (12) is connected to a pushing block (15) via a first spring telescopic rod (13). The side wall of the pushing block (15) is fixedly connected to a pushing rod (14), and the top of the pushing block (15) is provided with a friction mechanism for providing frictional resistance to the movement of the pushing block (15). The side wall of the lifting block (12) is provided with a clamping mechanism for clamping and limiting the puncture needle (11), and a limiting mechanism for limiting the movement of the pushing block (15) is provided between the pushing block (15) and the lifting block (12).

2. The neurosurgical puncture locator according to claim 1, characterized in that: The friction mechanism includes a fixed plate (201) fixedly connected to the side wall of the mounting head (104), and the top of the push block (15) is connected to a first moving block (202) through a first moving mechanism. The side wall of the first moving block (202) is rotatably connected to a rubber wheel (203) through a rotating mechanism, and the rubber wheel (203) abuts against the fixed plate (201).

3. The neurosurgical puncture locator according to claim 2, characterized in that: The first moving mechanism includes a fixed block (301) fixedly connected to the top of the push block (15), and a threaded rod (303) is rotatably connected to the side wall of the fixed block (301). A threaded tube (302) is threadedly connected to the side wall of the threaded rod (303), and the other end of the threaded tube (302) is fixed to the side wall of the first moving block (202). A first rocker wheel (304) is fixedly connected to one end of the threaded rod (303), and a guide assembly is provided between the fixed block (301) and the first moving block (202).

4. The neurosurgical puncture locator according to claim 3, characterized in that: The guide assembly includes two first guide rods (402) fixedly connected to the side wall of the fixed block (301), and each first guide rod (402) has a first guide tube (401) sleeved on its side wall. The other end of the first guide tube (401) is fixed to the side wall of the first moving block (202), and the side wall of the first guide rod (402) is provided with a scale mark (403).

5. A neurosurgical puncture locator according to claim 2, characterized in that: The rotating mechanism includes two mounting blocks (1001) fixedly connected to the side wall of the first moving block (202), and the rubber wheel (203) is rotatably connected to the side wall of the mounting block (1001) through the rotating shaft (1002).

6. The neurosurgical puncture locator according to claim 1, characterized in that: The guiding mechanism includes two second guide tubes (501) fixedly connected to the top of the mounting head (104), and a second guide rod (502) is inserted into each second guide tube (501), the upper end of the second guide rod (502) being fixed to the bottom of the lifting block (12).

7. The neurosurgical puncture locator according to claim 1, characterized in that: The clamping mechanism includes a U-shaped plate (601) fixedly connected to the side wall of the lifting block (12), and the side wall of the U-shaped plate (601) is connected to two moving plates (602) through a second moving mechanism. The opposite side walls of the two moving plates (602) are connected to two symmetrically arranged V-shaped blocks (604) through a second spring telescopic rod (603).

8. A neurosurgical puncture locator according to claim 7, characterized in that: The second moving mechanism includes two fixed rods (701) fixedly connected to the side wall of the U-shaped plate (601), and two moving plates (602) sleeved on the side wall of the fixed rods (701). A double-ended lead screw (702) is rotatably connected to the side wall of the U-shaped plate (601), and the moving plates (602) are threadedly connected to the threaded part of the double-ended lead screw (702). A second rocker wheel (703) is fixedly connected to one end of the double-ended lead screw (702).

9. A neurosurgical puncture locator according to claim 1, characterized in that: The limiting mechanism includes multiple arrayed limiting holes (801) on the side wall of the fixed plate (201), and a second moving block (802) is connected between the lifting block (12) and the pushing block (15) through a moving component. A conical block (803) is fixedly connected to the side wall of the second moving block (802), and the conical block (803) can be inserted into the limiting hole (801).

10. A neurosurgical puncture locator according to claim 9, characterized in that: The moving component includes a first link (901) rotatably connected between the push block (15) and the second moving block (802), and a second link (902) rotatably connected between the lifting block (12) and the second moving block (802).

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