Pre-tensioning method T-beam prefabricated pipe pile force transmission equipment

Abstract

The invention belongs to the technical field of civil engineering, and particularly relates to pre-tensioning method T-beam prefabricated tubular pile force transmission equipment which comprises mounting blocks arranged in an array mode, a base is slidably inserted between every two adjacent mounting blocks, force transmission columns are arranged on one side of a fixing block in an array mode, and the surfaces of the force transmission columns are fixedly sleeved with supporting components. A steel strand transversely penetrates through a body of the base, and an adjusting mechanism is arranged between the supporting components. According to the force transmission equipment, by arranging the adjusting mechanism, utilizing cooperation of a force unloading rod, a cross universal joint and other components and combining the decomposition and transmission rule of space force, the pressure of the steel strand on the force transmission columns during stretching can be balanced, so that the force transmission columns are stressed more uniformly, and the tensile strength of the steel strand is improved. And meanwhile, angle adjustment can be carried out between the force unloading rod and the first fixing block and the second fixing block which are connected with the force unloading rod according to the actual stress condition, part damage caused by local stress concentration is effectively avoided, the overall stress stability of equipment is improved, and the service life of the equipment is prolonged.

Description

Technical Field

[0001] This invention relates to the field of civil engineering technology, and in particular to a force transmission device for pre-tensioned T-beam precast pipe piles. Background Technology

[0002] In the field of civil engineering, pre-tensioned T-beams are widely used in the construction of superstructures for highway bridges, municipal viaducts, and railway branch lines due to their strong bending resistance, high structural stability, and excellent prefabrication efficiency. As the core load-bearing carrier in the prefabrication process of pre-tensioned T-beams, the performance of the force transmission equipment of the pipe pile directly determines the accuracy of the prestressing application of the T-beam, the quality stability of the prefabricated components, and the safety of the construction process. The force transmission equipment needs to uniformly transfer the prestress generated by the tensioning of the steel strands to the pipe pile body, while bearing the lateral, longitudinal, and vertical composite loads during the tensioning process. This ensures that the stress distribution of the pipe pile in the prefabrication stage meets the design requirements and avoids problems such as cracks in the T-beam and excessive prestress loss due to abnormal local stress.

[0003] However, the force transmission equipment for pre-tensioned T-beam precast pipe piles currently on the market still has many technical shortcomings in actual engineering applications, which seriously restrict construction efficiency and component quality. Specific problems include: poor force transmission balance, which easily leads to uneven stress distribution in pipe piles; cumbersome component assembly and disassembly, resulting in low construction efficiency; insufficient angle adaptability, severe local stress concentration; and lack of real-time stress monitoring function, resulting in high safety risks.

[0004] To address the aforementioned problems, this invention proposes a force transmission device for pre-tensioned T-beam precast pipe piles. Summary of the Invention

[0005] Based on the existing technical problems of uneven stress, cumbersome assembly, poor angle adaptation, and lack of monitoring, this invention proposes a force transmission device for pre-tensioned T-beam precast pipe piles.

[0006] The present invention proposes a force transmission device for pre-tensioned T-beam precast pipe piles, comprising arrayed mounting blocks, a base slidably inserted between two adjacent mounting blocks, force transmission columns arrayed on one side of the mounting blocks, a support component fixedly sleeved on the surface of the force transmission column, a steel strand passing through the body of the base, and an adjustment mechanism provided between the support components.

[0007] The adjustment mechanism is designed to balance the pressure exerted by the steel strand on the force transmission column during stretching.

[0008] Preferably, two adjacent force transmission columns arranged in an array are connected by a sliding plug-in method. One end of one force transmission column has an annular groove, and the inner wall of the annular groove has an array of rectangular grooves. One end of the rectangular grooves extends to the end face of the force transmission column, and the end face of the force transmission column has a slot array. One end of the other force transmission column is provided with a column that matches the slot, and one end of the force transmission column is provided with a limiting rod that matches the rectangular groove.

[0009] Preferably, the support component includes a first fixing block near the base, a universal joint is fixedly connected to one side of the first fixing block, a slot is opened on the other side of the first fixing block, a spring groove is opened on the inner wall of the slot, a first spring is fixedly connected to the inner wall of the spring groove, a limit block is fixedly connected to one end of the first spring, the right angle surface of the limit block is slidably connected to the inner wall of the spring groove, and a retaining ring is fixedly connected to the upper end of the first fixing block.

[0010] Preferably, a second fixing block is arranged in an array on one side of the first fixing block, and an adjustment groove is opened on the side of the second fixing block. The inner wall of the adjustment groove is symmetrically arranged with movable holes on both sides. A second spring is fixedly connected to the inner wall of the movable hole, and a limit post is fixedly connected to one end of the second spring. The two opposite limit posts do not contact each other.

[0011] Preferably, a rectangular slot is provided on the side of the base, and a sliding groove is symmetrically provided on one side of the rectangular slot along the axis of symmetry of the base. Circular holes are symmetrically arranged on the inner wall of the sliding groove along its vertical direction.

[0012] Preferably, the adjustment mechanism includes a relief rod disposed between two adjacent support components, one end of which is fixedly connected to a universal joint, and one end of the universal joint is fixedly connected to a slider adapted to the slide groove. A pin is slidably inserted into the inner wall of the circular hole, and one end of the pin passes through the surface of the slider to the interior of the circular hole on the other side.

[0013] Preferably, the base pressing force F, and the unloading rod receiving the base pressing force F3, wherein the components of F in the spatial coordinate system x, y, z axes are F0, F1, F2, and F3, and the direction cosines of F3 are... That is, the cosine of the angle between F3 and the x, y, z axes, satisfies Since the projection of the resultant force in a certain direction is equal to the algebraic sum of the projections of each component in that direction, the relationship between F and F3 is as follows: .

[0014] Preferably, the first fixing block is subjected to compressive force F4, and the angle between the forces F3 and F4 in the horizontal direction is... That is, the formula for both is: F4 = F3 .

[0015] Preferably, the distance between two adjacent limiting posts is h, the height of the lowest limiting post from the ground is H, the distance between the first fixing block and the second fixing block is L, and the force F5 on the second fixing block is: .

[0016] Preferably, pressure sensors are provided at the connection points between the first fixing block and the second fixing block and the unloading rod.

[0017] The beneficial effects of this invention are as follows: 1. By setting up an adjustment mechanism and utilizing components such as the unloading rod and universal joint, and combining the laws of spatial force decomposition and transmission, the pressure of the steel strand on the force transmission column during tension can be balanced, making the force transmission column more evenly stressed. At the same time, the angle between the unloading rod and the first and second fixed blocks it is connected to can be adjusted according to the actual stress conditions, effectively avoiding component damage caused by local stress concentration, and improving the overall stress stability and service life of the equipment.

[0018] 2. By setting a sliding plug-in docking structure between force transmission columns, it is not only convenient to quickly assemble and disassemble adjacent force transmission columns, but also to adapt to certain angle and position deformations when under stress, thereby improving the connection flexibility of the structure and its adaptability to complex stresses.

[0019] 3. By setting the first spring, second spring and cross universal joint in the support component, the universal joint can adapt to the angle change during the force transmission process, so that the support component has the ability to buffer and unload force, and can flexibly adapt to different force transmission angles, further ensuring the stable operation of the equipment under working conditions such as steel strand tension. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a force transmission device for pre-tensioned T-beam precast pipe piles proposed in this invention; Figure 2 This is a three-dimensional view of the force transmission column of a pre-tensioned T-beam precast pipe pile force transmission device proposed in this invention; Figure 3 This is a top view of a pre-tensioned T-beam precast pipe pile force transmission device proposed in this invention; Figure 4 This is a sectional view of the first fixing block of a force transmission device for pre-tensioned T-beam precast pipe piles proposed in this invention. Figure 5 This is a perspective view of the first fixing block of a force transmission device for pre-tensioned T-beam precast pipe piles proposed in this invention. Figure 6This is a three-dimensional view of the limiting block of a force transmission device for pre-tensioned T-beam precast pipe piles proposed in this invention; Figure 7 This is a perspective view of the base of a pre-tensioned T-beam precast pipe pile force transmission device proposed in this invention; Figure 8 This is a force analysis diagram of the base of a pre-tensioned T-beam precast pipe pile force transmission device proposed in this invention; Figure 9 This is a force analysis diagram of the first fixed block of a force transmission device for pre-tensioned T-beam precast pipe piles proposed in this invention. Figure 10 This is a vertical transmission diagram between the first and second fixed blocks of a force transmission device for pre-tensioned T-beam precast pipe piles proposed in this invention.

[0021] In the diagram: 1. Mounting block; 2. Force transmission column; 20. Annular groove; 21. Rectangular groove; 22. Slot; 23. Column; 24. Limiting rod; 3. Support component; 31. First fixing block; 32. First spring; 33. Limiting block; 34. Groove; 35. Second fixing block; 36. Snap ring; 37. Second spring; 38. Limiting column; 4. Steel strand; 5. Base; 51. Rectangular slot; 52. Round hole; 6. Adjustment mechanism; 61. Unloading rod; 62. Universal joint; 63. Slider. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] Reference Figures 1-10 A force transmission device for pre-tensioned T-beam precast pipe piles includes arrayed mounting blocks 1, a base 5 slidably inserted between two adjacent mounting blocks 1, a force transmission column 2 arrayed on one side of the mounting blocks 1, a support component 3 fixedly sleeved on the surface of the force transmission column 2, a steel strand 4 passing through the body of the base 5, and an adjustment mechanism 6 between the support components 3.

[0024] The adjustment mechanism 6 is used to balance the pressure of the steel strand 4 on the force transmission column 2 during stretching.

[0025] In this embodiment, two adjacent force transmission columns 2 arranged in an array are connected by a sliding plug-in method. One end of one force transmission column 2 is provided with an annular groove 20, and the inner wall of the annular groove 20 is provided with a rectangular groove 21. One end of the rectangular groove 21 extends to the end face of the force transmission column 2. The end face of the force transmission column 2 is provided with a slot 22 arranged in a circular array. One end of the other force transmission column 2 is provided with a column 23 that matches the slot 22, and one end of the force transmission column 2 is provided with a limiting rod 24 that matches the rectangular groove 21.

[0026] Specifically, the sliding insertion structure of adjacent force transmission columns 2 provides the movement space of the annular groove 20 for the limiting rod 24, preventing the components from jamming during docking; the cooperation between the rectangular groove 21 and the limiting rod 24 can restrict the rotation of the force transmission column 2 around the axis, ensuring the stability of the force transmission direction; the insertion of the slot 22 and the column 23 achieves axial positioning, ensuring the coaxiality of adjacent force transmission columns 2; when the steel strand 4 is stretched and generates lateral force, it avoids local stress concentration caused by rigid docking, while not affecting the overall force transmission efficiency.

[0027] In this embodiment, the support component 3 includes a first fixing block 31 near the base 5. A universal joint is fixedly connected to one side of the first fixing block 31. A slot 34 is opened on the other side of the first fixing block 31. A spring groove is opened on the inner wall of the slot 34. A first spring 32 is fixedly connected to the inner wall of the spring groove. A limit block 33 is fixedly connected to one end of the first spring 32. The right-angled surface of the limit block 33 is slidably connected to the inner wall of the spring groove. A retaining ring 36 is fixedly connected to the upper end of the first fixing block 31.

[0028] Specifically, the universal joint 62 is the core angle adaptation component of the first fixed block 31, which can realize multi-angle force transmission within a range of ±15°. When the unloading rod 61 tilts due to force, the universal joint 62 can adjust the angle synchronously to ensure stable force transmission. The slot 34 is used to accommodate the extension part of the force transmission column 2, forming a sleeve and limiting structure to prevent the first fixed block 31 from sliding along the axial direction of the force transmission column 2. The retaining ring 36 provides auxiliary positioning for the steel strand 4 to prevent the steel strand 4 from shifting laterally during tensioning and to ensure that its tension direction is consistent with the force transmission direction of the force transmission column 2.

[0029] In this embodiment, a second fixing block 35 is arranged in an array on one side of the first fixing block 31. An adjustment groove is opened on the side of the second fixing block 35. Movable holes are symmetrically arranged on both sides of the inner wall of the adjustment groove. A second spring 37 is fixedly connected to the inner wall of the movable hole. A limit post 38 is fixedly connected to one end of the second spring 37. The two opposite limit posts 38 do not contact each other.

[0030] Specifically, the width of the adjustment groove is designed to be 1.05-1.1 times the diameter of the force transmission column 2, which ensures that the second fixing block 35 can be stably fitted onto the force transmission column 2, while also reserving a small adjustment space; the second spring 37 in the movable hole ensures that the limiting column 38 always has a pressing force toward the center of the adjustment groove, and a gap is reserved between the two relative limiting columns 38 to avoid them colliding with each other during vibration and generating noise or wear, while ensuring that the limiting column 38 fixes the unloading rod 61.

[0031] In this embodiment, a rectangular slot 51 is provided on the side of the base 5, and a sliding groove is symmetrically provided on one side of the rectangular slot 51 along the axis of symmetry of the base 5. Circular holes 52 are symmetrically arranged on the inner wall of the sliding groove along its vertical direction.

[0032] Specifically, when the rectangular slot 51 is slidably inserted, the base 5 and the mounting block 1 can be seamlessly connected, avoiding relative shaking between the two due to gaps; the diameter of the round hole 52 is a transition fit with the diameter of the pin, and after the pin passes through the slider 63, it can completely restrict the movement of the slider 63 in the groove, ensuring that the position of the adjustment mechanism 6 is stable during force transmission. At the same time, the pin is made of high-strength alloy steel to avoid bending or breaking under force.

[0033] In this embodiment, the adjustment mechanism 6 includes a relief rod 61 disposed between two adjacent support components 3. One end of the relief rod 61 is fixedly connected to a universal joint 62. One end of the universal joint 62 is fixedly connected to a slider 63 that is adapted to the slide groove. A pin is slidably inserted into the inner wall of the circular hole 52. One end of the pin passes through the surface of the slider 63 to the interior of the circular hole 52 on the other side.

[0034] Specifically, the unloading rod 61 adopts a hollow round tube structure, which reduces its weight while ensuring a tensile strength of ≥345MPa; the universal joint 62 has a maximum bending angle of 30° and a built-in self-lubricating bearing to ensure that it can still rotate flexibly after long-term use and avoid interruption of force transmission due to jamming; the length of the pin needs to cover both sides of the slide groove of the base 5, and an anti-slip pin cap is set at one end to prevent the pin from falling off during vibration and to ensure the connection reliability of the adjustment mechanism 6.

[0035] In this embodiment, the base 5 exerts a compressive force F, and the unloading rod 61 receives a compressive force F3 from the base 5. The components of F along the x, y, and z axes of the spatial coordinate system are F0, F1, F2, and F3, with direction cosines of F3 as follows: That is, the cosine of the angle between F3 and the x, y, z axes, satisfies Since the projection of the resultant force in a certain direction is equal to the algebraic sum of the projections of each component in that direction, the relationship between F and F3 is as follows: .

[0036] Specifically, when the steel strand 4 is stretched, the pressure sensor identifies the force value of the first fixing block 31. If the value exceeds the preset value, the operator can adjust the angle between the unloading rod 61 and the base 5 so that the force value of the base 5 is within a safe range and further protects the stability of the force transmission column 2.

[0037] In this embodiment, the first fixing block 31 is subjected to compressive force F4, and the angle between the forces F3 and F4 in the horizontal direction is... That is, the formula for both is: F4 = F3 .

[0038] Specifically, since the first fixed block 31 mainly bears the horizontal load, while the vertical load is borne by the force transmission column 2, the horizontal component of F3 needs to be extracted as F4 through the cosine function. This calculation result is used for the structural design of the first fixed block 31, such as determining its thickness and the specifications of the connecting bolts, to ensure that the first fixed block 31 can withstand the actual horizontal compressive force without deformation.

[0039] In this embodiment, the distance between two adjacent limiting posts 38 is h, the height of the lowest limiting post 38 from the ground is H, the distance between the first fixing block 31 and the second fixing block 35 is L, and the force F5 on the second fixing block 35 is: .

[0040] Specifically, when the torque generated by the force F4 on the first fixed block 31 is transmitted to the second fixed block 35 through the unloading rod 61, the force needs to be distributed according to the sum of the horizontal distance L between the two and the height of the limiting post h+H to ensure that the bearing capacity of the second fixed block 35 matches the actual force, and to avoid the second fixed block 35 falling off due to torque overload. If the distance between one end of the unloading rod 61 and the ground is higher, the force F5 is smaller, and the squeezing force on the subsequent second fixed block 35 is smaller.

[0041] In this embodiment, pressure sensors are provided at the connection points between the first fixing block 31 and the second fixing block 35 and the unloading rod 61.

[0042] Specifically, the pressure sensor adopts piezoelectric or strain gauge type, with a measurement range of 0-500kN and an accuracy of ±1%. It is fixed in the reserved mounting hole at the connection point by bolts. Its core functions include two points: first, real-time monitoring, during the tensioning process of the steel strand 4, the values ​​of F3, F4, and F5 are collected in real time and transmitted to the control console; second, overload protection, when the force on a certain part exceeds the design threshold, the sensor triggers an alarm signal, and the tensioning equipment automatically stops to avoid damage to the components due to overload.

[0043] Reference Figures 1-10 A construction method for a pre-tensioned T-beam precast pipe pile force transmission device, the specific steps of which are as follows: Step 1: First, according to the preset height and pressure data values, fix the slider 63 at one end of the unloading rod 61 into the round hole 52 using a pin. At this time, the force transmission of the unloading rod 61 is within the safe range. Then, slide the base 5 into the reserved slot of the mounting block 1. There is one base 5 between every two adjacent mounting blocks 1. After insertion, check the fit clearance between the rectangular slot 51 of the base 5 and the mounting block 1. If the clearance is too large, use thin steel plate shims to adjust it to ensure that the base 5 does not wobble laterally. At the same time, use a level to check the fit clearance. The levelness of the base 5 is calibrated. If the deviation exceeds the limit, it is corrected by adjusting the bolts at the bottom of the base. Then, the force transmission columns 2 are assembled in array order. The uprights 23 of the adjacent force transmission columns 2 are inserted into the slots 22 and the limiting rods 24 are inserted into the rectangular slots 21. After docking, the force transmission columns 2 are shaken by hand to ensure that there is no looseness and that they can flexibly produce a small angular displacement. Then, the first fixing block 31 and the second fixing block 35 are respectively fitted into the preset positions of the force transmission columns 2. The support component 3 is fixed to the force transmission column 2 with fastening bolts to prevent axial sliding. Step 2: The universal joint 62 at one end of the unloading rod 61 is fixedly connected to the reserved position of the first fixing block 31 with bolts. Then, the other unloading rod 61 is slid along the groove 34 to its bottom. The arc-shaped groove at the lower end of the limiting block 33 limits and engages the unloading rod 61. The other end of the unloading rod 61 is pressed against the limiting post 38 in the second fixing block 35 adjacent to the first fixing block 31. The limiting post 38 is pressed against the second spring 37 until one end of the limiting post 38 is inserted into the hole at the end of the unloading rod 61. At this point, the installation steps of the second fixing block 35 and the unloading rod 61 are completed. Subsequent installations can refer to the above steps. Step 3: Start the tensioning equipment and stretch the steel strand 4 according to the graded loading principle. After each loading stage, pause for 3-5 minutes to observe whether there are any abnormalities in the various components of the equipment. During the loading process, check the F3, F4, and F5 values ​​displayed on the control panel in real time and record the force data of each part. If the F4 and F5 values ​​corresponding to a certain force transmission column 2 are found to deviate by more than 5%, stop tensioning, release the fixing effect of the mounting block 1 which is fixed to the ground surface by bolts, remove the mounting block 1 with external mechanical equipment, and then loosen the pin of the adjustment mechanism 6 of that part. Move the slider 63 to adjust the angle of the unloading rod 61. Raising the slider 63 will increase F4, and lowering the slider 63 will decrease F4. After adjustment, re-fix the pin and repeat the graded loading until the force is balanced.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A force transmission device for pre-tensioned T-beam precast pipe piles, comprising arrayed mounting blocks (1), characterized in that: A base (5) is slidably inserted between two adjacent mounting blocks (1). A force transmission column (2) is arranged in an array on one side of the mounting block (1). A support component (3) is fixedly sleeved on the surface of the force transmission column (2). A steel strand (4) runs through the body of the base (5). An adjustment mechanism (6) is arranged between the support components (3). The adjustment mechanism (6) is used to balance the pressure of the steel strand (4) on the force transmission column (2) when it is stretched.

2. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 1, characterized in that: The two adjacent force transmission columns (2) arranged in an array are connected by a sliding plug-in method. One end of one of the force transmission columns (2) is provided with an annular groove (20). The inner wall of the annular groove (20) is provided with a rectangular groove (21). One end of the rectangular groove (21) extends to the end face of the force transmission column (2). The end face of the force transmission column (2) is provided with a slot (22) arranged in a circular array. One end of the other force transmission column (2) is provided with a column (23) that matches the slot (22). One end of the force transmission column (2) is provided with a limiting rod (24) that matches the rectangular groove (21).

3. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 2, characterized in that: The support component (3) includes a first fixing block (31) near the base (5). A universal joint is fixedly connected to one side of the first fixing block (31). A slot (34) is opened on the other side of the first fixing block (31). A spring groove is opened on the inner wall of the slot (34). A first spring (32) is fixedly connected to the inner wall of the spring groove. A limit block (33) is fixedly connected to one end of the first spring (32). The right angle surface of the limit block (33) is slidably connected to the inner wall of the spring groove. A retaining ring (36) is fixedly connected to the upper end of the first fixing block (31).

4. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 3, characterized in that: A second fixing block (35) is arranged on one side of the first fixing block (31). An adjustment groove is opened on the side of the second fixing block (35). Movable holes are symmetrically arranged on both sides of the inner wall of the adjustment groove. A second spring (37) is fixedly connected to the inner wall of the movable hole. A limit post (38) is fixedly connected to one end of the second spring (37). The two opposite limit posts (38) do not contact each other.

5. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 4, characterized in that: The base (5) has a rectangular slot (51) on its side. A sliding groove is symmetrically provided on one side of the rectangular slot (51) along the axis of symmetry of the base (5). Circular holes (52) are symmetrically arranged on the inner wall of the sliding groove along its vertical direction.

6. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 5, characterized in that: The adjustment mechanism (6) includes a relief rod (61) disposed between two adjacent support components (3), one end of which is fixedly connected to a universal joint (62), and one end of the universal joint (62) is fixedly connected to a slider (63) adapted to the slide groove. A pin is slidably inserted into the inner wall of the circular hole (52), and one end of the pin passes through the surface of the slider (63) to the interior of the circular hole (52) on the other side.

7. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 6, characterized in that: The base (5) exerts a compressive force F, and the unloading rod (61) receives a compressive force F3 from the base (5), wherein the components of F in the spatial coordinate system x, y, z axes are F0, F1, F2, and F3, and the direction cosines of F3 are... That is, the cosine of the angle between F3 and the x, y, z axes, satisfies Since the projection of the resultant force in a certain direction is equal to the algebraic sum of the projections of each component in that direction, the relationship between F and F3 is as follows: .

8. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 7, characterized in that: The first fixed block (31) is subjected to compressive force F4, and the angle between the forces F3 and F4 in the horizontal direction is... That is, the formula for both is: F4 = F3 .

9. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 8, characterized in that: The distance between two adjacent limiting posts (38) is h, the height of the lowest limiting post (30) from the ground is H, the distance between the first fixing block (31) and the second fixing block (35) is L, and the force F5 on the second fixing block (35) is: .

10. The force transmission device for pre-tensioned T-beam precast pipe piles according to claim 9, characterized in that: Pressure sensors are provided at the connection points of the first fixing block (31) and the second fixing block (35) with the unloading rod (61).

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