Gravity type clamp
By linking the cross-hinged clamping arms and pulley assembly of the gravity clamp, the automatic clamping and release of concrete components is achieved, solving the cost and safety problems of traditional hoisting methods and improving construction efficiency and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2026-03-13
AI Technical Summary
Existing methods for hoisting concrete components require reserving hoisting points, which increases costs and operational complexity, and poses safety hazards, especially in confined spaces or complex working conditions where operation is inconvenient.
Design a gravity clamp that uses the weight of the component to achieve clamping. Through the linkage of the cross-hinged clamping arms and the pulley assembly, automatic clamping and release can be achieved, avoiding manual unhooking.
No need to reserve lifting points, reducing costs, improving safety and portability, increasing construction efficiency, and adapting to the clamping needs of components of different sizes.
Smart Images
Figure CN223990813U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of engineering construction technology, and in particular to a gravity clamp. Background Technology
[0002] Concrete components are typically transported and installed using wire rope hoisting. This method usually requires pre-installed hoisting points on the concrete components, which increases the number of steps and costs involved in the concrete component manufacturing process. Furthermore, it necessitates manual assistance in unhooking, which limits portability, especially during underwater installation of precast concrete components. In addition, traditional hoisting methods pose safety hazards, particularly when hoisting large or heavy concrete components. The binding and securing of wire ropes requires high technical skills, and improper operation can lead to component detachment or damage. Utility Model Content
[0003] To overcome the problems existing in related technologies, this utility model provides a gravity clamp that can achieve clamping by utilizing the self-weight of the components, without the need for manual assistance in unhooking, and has the advantages of reducing costs, improving safety and portability.
[0004] This utility model provides a gravity clamp, including a lifting wire rope, a slack wire rope, a lifting pulley, and two symmetrical and cross-hinged clamping arms;
[0005] The first end of the clamping arm is provided with a clamping palm and a release hook lifting point, the clamping palms of the two clamping arms are arranged opposite each other, and the second end of the clamping arm is provided with a clamping pulley;
[0006] The lifting pulley's shaft is connected to a connecting rod, which is hinged to the second end of the clamping arm;
[0007] The lifting wire rope is wound around two clamping pulleys and then connected to the main hook of the lifting equipment.
[0008] One end of the slack hook wire rope is connected to the auxiliary hook of the lifting equipment, and the other end is connected to the slack hook lifting point.
[0009] In some embodiments, the clamping palm is mounted on the clamping arm via a first pin, the two clamping arms are cross-hinged via a second pin, and the connecting rod is hinged to the clamping arm via a third pin.
[0010] Wherein, the vertical distance between the first pin and the second pin is L1, the vertical distance between the second pin and the clamping pulley axis is L2, and the vertical distance between the second pin and the third pin is L3, wherein L2≥2L1 and L3≥1.5L1.
[0011] In some implementations, the clamping force of the two clamping arms is greater than twice the weight of the object being lifted, under the action of the lifting wire rope.
[0012] In some embodiments, the second end of the clamping arm is further provided with a guide pulley, and the release wire rope is connected to the release point and the auxiliary hook after being guided by the guide pulley.
[0013] In some embodiments, the horizontal distance between the axis of the guide pulley and the second pin is less than the horizontal distance between the hook slack point and the second pin.
[0014] In some embodiments, the lifting pulley, clamping pulley, and guide pulley are all equipped with rope protection devices to prevent the wire rope from coming off.
[0015] In some embodiments, the lifting pulley has two discs, and the two ends of the lifting wire rope are guided by the two discs and then connected to the main hook.
[0016] In some embodiments, the palm clamp surface is provided with transverse anti-slip grooves.
[0017] In some embodiments, the clamping arm is provided with a limiting mechanism to limit the swing amplitude of the clamping hand.
[0018] In some embodiments, the limiting mechanism includes a limiting bolt, which is threadedly connected to the clamping arm, and the clamping palm has an arc-shaped hole in which the limiting bolt is accommodated.
[0019] The technical solution provided by this utility model can include the following beneficial effects:
[0020] The gravity clamp provided by this utility model, through the linkage design of symmetrical hinged clamping arms and pulley assembly, automatically generates clamping force by gravity during the lifting process, eliminating the need for manual assistance in unhooking. This solves the problems of reserving lifting points and operational safety hazards in the traditional lifting of concrete components, and has the advantages of reducing costs, improving safety and portability. Attached Figure Description
[0021] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally represent like parts.
[0022] Figure 1 This is a front view of the gravity clamp shown in an embodiment of the present utility model;
[0023] Figure 2 This is a diagram showing the lever arm relationship of the gravity clamp according to an embodiment of the present invention;
[0024] Figure 3 This is a side view of the gravity clamp shown in an embodiment of the present invention.
[0025] Figure label:
[0026] 1. Lifting wire rope; 2. Release wire rope; 3. Lifting pulley; 4. Clamping arm; 5. Clamping hand; 6. Release point; 7. Clamping pulley; 8. Connecting rod; 9. Main hook; 10. Auxiliary hook; 11. First pin; 12. Second pin; 13. Third pin; 14. Guide pulley; 15. Rope protection device; 16. Limiting mechanism; 17. Lifted object. Detailed Implementation
[0027] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.
[0028] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.
[0029] It should be understood that although the terms "first," "second," "third," etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0030] In existing technologies, concrete components are often hoisted using steel wire rope binding, which requires pre-reserved hoisting points on the components. This not only increases the manufacturing process and cost but also requires manual assistance to unhook the ropes, resulting in cumbersome operation and limited efficiency. Especially in confined spaces or complex working conditions, traditional hoisting methods pose safety hazards and are inconvenient to operate.
[0031] To address the aforementioned issues, a lifting device requiring no pre-reserved lifting points and capable of rapid self-locking needs to be developed. By analyzing the feasibility of combining wire rope transmission with the lever principle, the inventors discovered that gravity self-locking can be achieved through a cross-hinged clamping arm structure. Simultaneously, considering the coordinated action of the main and auxiliary hooks, a linkage mechanism controlling clamping and releasing via a pulley system was conceived.
[0032] To address the aforementioned problems, this utility model provides a gravity clamp that utilizes the self-weight of the components to achieve clamping without requiring manual assistance in unhooking, thereby improving construction efficiency and operational safety.
[0033] The technical solutions of the embodiments of this utility model are described in detail below with reference to the accompanying drawings.
[0034] See Figures 1-3 This utility model proposes a gravity clamp, including a lifting wire rope 1, a loosening wire rope 2, a lifting pulley 3, and two symmetrical and cross-hinged clamping arms 4;
[0035] The first end of the clamping arm 4 is provided with a clamping palm 5 and a loosening hook lifting point 6. The clamping palms 5 of the two clamping arms 4 are arranged opposite each other. The second end of the clamping arm 4 is provided with a clamping pulley 7.
[0036] The lifting pulley 3 has a connecting rod 8 connected to its rotating shaft, and the connecting rod 8 is hinged to the second end of the clamping arm 4.
[0037] The lifting wire rope 1 is wound around two clamping pulleys 7 and a lifting pulley 3 and then connected to the main hook 9 of the lifting equipment;
[0038] One end of the slack hook wire rope 2 is connected to the auxiliary hook 10 of the lifting equipment, and the other end is connected to the slack hook lifting point 6.
[0039] The lifting wire rope 1 and the slack wire rope 2 can be formed by twisting together multiple strands of high-strength steel wire. The clamping arm 4 is a box girder structure, a hollow structure with a closed box-shaped cross-section, consisting of a top plate, bottom plate, web plate, and flange plate. Internal diaphragms can be installed to enhance overall rigidity and torsional resistance. The clamping arm 4 is composed of a first straight section, an inclined section, and a second straight section spliced together, with a rounded transition between the two sections. The first straight section is parallel to the second straight section, and a through hole is provided in the middle of the inclined section. The two clamping arms 4 are hinged together through their respective through holes to form an X-shaped structure. The clamping palm 5 is located at the end of the clamping arm 4, i.e., the end furthest from the main hook 9. The two clamping palms 5 are located on opposite sides of the two clamping arms 4, and can be rotatably connected to the clamping palm 5 to ensure that the clamping palm 5 can conform to the surface of different suspended objects 17. The X-shaped structure formed by the cross hinge can make the two ends of the clamping arm 4 act as a lever. After the lifting wire rope 1 is guided by the lifting pulley 3, the horizontal component of the force is transmitted to the clamping pulley 7, so that the two clamping hands 5 are brought closer to each other to achieve the purpose of lifting the object 17.
[0040] Two clamping pulleys 7 are wound around the lifting wire rope 1 and fixed to the second end of the clamping arm 4, forming a fixed pulley structure. The clamping pulleys 7 are used to change the direction of force on the lifting wire rope 1 and apply a horizontal component force to the clamping arm 4. The lifting pulley 3 is movably connected to the clamping arm 4 through a connecting rod 8. The connecting rod 8 serves as the support structure for the lifting pulley 3. Both connecting rods 8 can rotate relative to the clamping arm 4 and the lifting pulley 3, so that they can support the lifting pulley 3 to move closer to or away from the clamping arm 4 within a certain range, thus forming a movable pulley structure. In conjunction with the clamping pulleys 7, it can significantly improve the clamping force on the suspended object 17. The release hook lifting point 6 is installed on the clamping arm 4 near the clamping hand 5. The release hook lifting point 6 can adopt a lifting lug structure and be fixed to the clamping arm 4 by welding. The connection line between the release hook lifting point 6 and the auxiliary hook 10 is inclined to the vertical line so as to transmit the traction force of the two clamping arms 4 rotating around the hinge point.
[0041] Specifically, when the main hook 9 is lifted, the lifting wire rope 1 pulls the two clamping arms 4 to rotate around the hinge point through the clamping pulley 7 and the lifting pulley 3. The tension of the wire rope causes the first and second ends of the two clamping arms 4 to contract inward simultaneously, that is, the two clamping palms 5 move closer to each other, and the clamping palms 5 close to clamp the suspended object 17 through the lever principle. During the lifting process of the main hook 9, the clamping force of the clamping palms 5 on the suspended object 17 is gradually increased by the clamping pulley 7. When the suspended object 17 is off the ground, the clamping force applied to the suspended object 17 by the clamping palms 5 is greater than or equal to the self-weight of the suspended object 17, thereby realizing the transportation of the suspended object 17. In other words, the clamping force is formed by the combined action of the self-weight of the component and the tension of the wire rope to create the self-locking of the suspended object 17. After the suspended object 17 is moved to the desired position, the main hook 9 is lowered so that the suspended object 17 touches the ground. Then the main hook 9 is lowered slightly so that the clamping pulley 7 no longer applies the outward contraction horizontal component force to the clamping arm 4. At this time, the auxiliary hook 10 can be raised, and the loosening wire rope 2 pulls the two clamping arms 4 to expand outward, forcing the clamping hand 5 to release the suspended object 17.
[0042] As can be seen from the above technical solution, although the clamps 5 no longer grip the suspended object 17 after the main hook 9 descends and the object 17 contacts the ground, the two clamps 5 still have a certain limiting function on the suspended object 17. Manually pushing the clamps 5 to release it from the object 17 is not only limited by the confined operating space, but also increases the risk of the operation because the operator must stand below the main hook 9. Therefore, the purpose of this utility model is to enhance the safety of the operation by configuring a release wire rope 2, ensuring smooth handling and installation operations even in extremely confined areas.
[0043] In this embodiment, the present invention achieves hoisting of concrete components without pre-reserved lifting points, eliminating the cost of pre-embedded parts. The clamping process is entirely automated by gravity and pulley mechanisms, requiring no manual intervention for rope threading. The hook release action is achieved through the auxiliary hook 10, reducing the operational risk of hook release. The leverage effect formed by the cross-hinged structure ensures the reliability of the clamping force and can adapt to the clamping needs of components of different sizes.
[0044] The density of cured concrete is typically maintained between 2200 and 2500 kg / m³, characterized by its small volume and large mass. To ensure smooth lifting of irregular components such as trough-shaped and X-shaped concrete without damage, this invention further proposes that the clamping arm 5 is mounted on the clamping arm 4 via a first pin 11, the two clamping arms 4 are cross-hinged via a second pin 12, and the connecting rod 8 is hinged to the clamping arm 4 via a third pin 13.
[0045] Wherein, the vertical distance between the first pin 11 and the second pin 12 is L1, the vertical distance between the second pin 12 and the axis of the clamping pulley 7 is L2, and the vertical distance between the second pin 12 and the third pin 13 is L3, wherein L2≥2L1 and L3≥1.5L1.
[0046] The first pin 11 serves as the fulcrum for the rotation of the clamping hand 5 and the clamping arm 4, ensuring that the clamping hand 5 can adapt to the surfaces of different objects 17 being lifted. The second pin 12 is the center point where the two clamping arms 4 are hinged. The third pin 13 is used by the connecting rod 8 to move the lifting pulley 3 relative to the clamping arm 4. The constraint L2≥2L1 creates a lever amplification effect relative to the hinge center of the clamping pulley 7, thereby converting the displacement of the end of the clamping arm 4 into the clamping force of the clamping hand 5. The constraint L3≥1.5L1 ensures that the hinge point between the connecting rod 8 and the clamping arm 4 is located behind the center of gravity of the clamping arm 4, forming a stable lever arm relationship during lifting.
[0047] Specifically, when the main hook 9 lifts the lifting wire rope 1, the horizontal component of the lifting wire rope 1 is transmitted to the clamping pulley 7, which in turn drives the two clamping arms 4 to rotate and close around the second pin 12. Due to the ratio of L2 to L1, the displacement of the clamping pulley 7 is converted into the clamping force of the clamping hand 5, while the size constraint of L3 keeps the clamping arms 4 in line of force balance during the closing process.
[0048] Furthermore, under the action of the lifting wire rope 1, the clamping force of the two clamping arms 4 is greater than twice the weight of the object being lifted 17.
[0049] The clamping force refers to the vertical pressure applied by the clamping arm 4 to the surface of the suspended object 17 through the clamping hand 5, which is also the horizontal component of the lifting wire rope 1. This horizontal component can be achieved by adjusting the traction angle of the lifting wire rope 1 between the lifting pulley 3 and the clamping pulley 7, and its function is to provide sufficient friction for the clamping hand 5 to prevent slippage during the lifting process. The self-weight of the suspended object 17 refers to the total mass of the object under gravity, which can be obtained by measurement or calculation. It serves as a benchmark parameter for the clamping force design to ensure a safe proportional relationship between the clamping force and the load. Setting the clamping force to twice the weight of the suspended object 17 can prevent cracking of the concrete material of the suspended object 17.
[0050] In this embodiment, the lifting load is transmitted and amplified by a mechanical structure, so that the clamping force and the load form a certain proportional relationship. The clamping force can automatically maintain a stable clamping state without manual intervention. The clamping force and the self-weight form a fixed proportional relationship, avoiding the risk of slippage due to insufficient clamping. At the same time, the manual unhooking process is eliminated, improving the automation and safety of the lifting operation.
[0051] Furthermore, the second end of the clamping arm 4 is also provided with a guide pulley 14, and the slack hook wire rope 2 is connected to the slack hook lifting point 6 and the auxiliary hook 10 after being guided by the guide pulley 14.
[0052] The release point 6 is located between the first pin 11 and the second pin 12 of the clamping arm 4. The guide pulley 14 is located on one side of the clamping pulley 7 and is a fixed pulley used to change the direction of movement of the release wire rope 2. By changing the traction path of the release wire rope 2, the vertical component of the force transmitted from the release wire rope 2 to the clamping arm 4 can be changed, thus avoiding the problem of breakage due to excessive force on the release point 6.
[0053] In addition, an outwardly extending bracket can be provided between the first pin 11 and the second pin 12 of the clamping arm 4, and the hook release point 6 is installed on the bracket. This arrangement can further reduce the vertical component of the force applied by the hook release wire rope 2 to the hook release point 6, and can release the self-locking of the clamping arm 4 more quickly.
[0054] Furthermore, the horizontal distance between the axis of the guide pulley 14 and the second pin 12 is less than the horizontal distance between the hook slack point 6 and the second pin 12.
[0055] Furthermore, the lifting pulley 3, clamping pulley 7, and guide pulley 14 are all equipped with a rope protection device 15 to prevent the wire rope from coming off. The rope protection device 15 can be a metal baffle or a U-shaped cover. Its function is to constrain the movement trajectory of the wire rope in the pulley groove, solve the problem of lifting failure caused by the wire rope coming off, avoid equipment damage and work interruption caused by the wire rope coming off the groove, and improve work efficiency and safety.
[0056] Furthermore, the lifting pulley 3 has two discs. The two ends of the lifting wire rope 1 are guided by the two discs and then connected to the main hook 9. The lifting wire rope 1 is guided separately by the two independent discs, which can prevent the wire rope from crossing and winding due to the single disc structure, and avoid the problems of clamping failure and equipment damage.
[0057] Furthermore, the surface of the clamp 5 is provided with transverse anti-slip grooves. The transverse anti-slip grooves can be achieved by using equidistantly distributed V-shaped grooves or U-shaped grooves. The ratio of groove depth to groove width can be adjusted according to the surface roughness of the suspended object 17, which can effectively increase the contact friction coefficient.
[0058] Furthermore, the clamping arm 4 is provided with a limiting mechanism 16 to limit the swing amplitude of the clamping palm 5. Specifically, the limiting mechanism 16 includes a limiting bolt, which is threadedly connected to the clamping arm 4. The clamping palm 5 is provided with an arc-shaped hole, and the limiting bolt is housed in the arc-shaped hole. The arc-shaped hole provides swing space for the clamping palm 5. When the clamping palm 5 swings to the limit position, the limiting bolt contacts the edge of the arc-shaped hole to form a hard limit.
[0059] In summary, when applying the technical solution of this utility model, the lifting wire rope 1 and the slack wire rope 2 are wound as required and hung on the main hook 9 and the auxiliary hook 10 of the crane respectively. The clamped side of the suspended object 17 faces upward. The auxiliary hook 10 is raised, the slack wire rope 2 opens the clamp, and the main and auxiliary hooks 10 descend simultaneously, so that the clamping hand 5 of the clamp is on the side of the suspended object 17. When the clamp is lowered to its lowest point, the auxiliary hook 10 descends, and the clamping hand 5 of the clamp is placed against the side of the suspended object 17.
[0060] Assume the weight of the object being lifted 17 is Q, the weight of the clamp is Gjj, the main lifting hook 9, and the lifting wire rope 1 is tightened through the pulley block to pull the clamp arm 41 and clamp arm 42 towards the middle. The single rope tension of the lifting wire rope 1 is Fgss=(Q+Gjj) / 2.
[0061] Where the included angle between the two connecting rods 8 is b, then the horizontal tension of connecting rod 8 is Flg=Fgss / cos(b / 2).
[0062] The clamping pulley 7 has two steel wire ropes in the transverse direction. According to the torque balance, 2×Fgss×L2+Flg×sin(b / 2)×L3=Fj×L1, the clamping pressure Fj=(2×Fgss×L2+Flg×sin(b / 2)×L3) / L1. The friction coefficient between the clamp 5 and the suspended object 17, taking the static friction coefficient between steel structure and concrete as an example, can be taken as 0.5~0.75, taking the lower value of 0.5. The clamping force of the clamp on the suspended object 17 is Fjc=0.5×Fj, which can ensure that the ratio of the clamping force of the clamp to the weight of the suspended object 17 is S=Fjc / (Q+Gjj)≥2.
[0063] The clamping force of the clamp is always maintained at no less than twice the weight of the object 17 being lifted, ensuring a safe and reliable lifting process. Simultaneously, the auxiliary hook 10 can be used to lift or lower the slack wire rope 2, enabling automatic release of the hook, reducing manual assistance and improving lifting efficiency.
[0064] Corresponding to the foregoing embodiments, this application also provides an application example of the gravity clamp disclosed in the above embodiments. Specifically, in the construction of a breakwater, precast concrete components (such as trough-shaped concrete or X-shaped concrete, with a self-weight of up to 32 tons) need to be placed in shallow sea between 30 and 100 meters offshore. Because the placement of the concrete components is rather haphazard, there may be no space for personnel to stand and operate between them, or there may be a risk of loosening between the components. Using traditional methods of binding and unhooking steel wire ropes is inefficient and risky. With this gravity clamp, unmanned clamping and release can be achieved.
[0065] The specific operating steps are as follows:
[0066] 1. Fixture pre-installation
[0067] 1.1 The gravity clamp is suspended below the crane boom via the main hook 9, and the loose wire rope 2 is connected to the auxiliary hook 10.
[0068] 1.2 With the assistance of the operator, the clamp is initially positioned on the side of the protruding part of the X-shaped concrete component, ensuring that the clamping hand 5 is aligned with the flat areas on both sides of the protruding part.
[0069] 1.3 The transverse anti-slip grooves on the surface of the 1.3 clamp palm 5 contact the concrete surface to enhance friction.
[0070] 2. Automatic clamping
[0071] 2.1 The main hook 9 of the crane is slowly lifted, and the lifting wire rope 1 is tightened through the clamping pulley 7 and the lifting pulley 3, which drives the two clamping arms 4 to close around the second pin 12.
[0072] 2.2 The combined weight of the clamp and the X-shaped concrete component amplifies the clamping force through the lever ratio (L2≥2L1), thus lifting the X-shaped concrete component.
[0073] 2.3 The rope protection device 15 ensures that the lifting wire rope 1 and the slack wire rope 2 do not come out of the groove when the clamp moves, and the limiting mechanism 16 limits the swing amplitude of the clamp 5 to ensure that the clamp 5 and the protrusion can be subjected to uniform force.
[0074] 3. Hoisting
[0075] 3.1 The crane will lift the X-shaped concrete to the target coastline.
[0076] 3.2 The cross-hinged structure of clamping arm 4 adapts to the slight tilt of the X-shaped concrete component, and the clamping force is dynamically adjusted with its own weight to ensure hoisting stability.
[0077] 4. Precise release
[0078] 4.1 The X-shaped concrete component is located above the designated coastline. The X-shaped concrete component is brought into contact with the ground or stacked on top of other X-shaped concrete components by lowering the main hook. The main hook 9 is slightly lowered to release the self-locking of the clamp arm 4, and the auxiliary hook 10 is simultaneously raised to release the wire rope 2.
[0079] 4.2 The guide pulley 14 changes the direction of the loosening wire rope 2, and the traction clamp arm 4 expands outward around the second pin shaft 12, and the clamping palm 5 automatically disengages from the X-shaped concrete component.
[0080] 4.3 No operator intervention is required. The entire process is completed through the coordinated operation of the crane, avoiding the operational risks of manual unhooking by personnel.
[0081] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A gravity clamp, characterized in that, It comprises a lifting wire rope (1), a loose hook wire rope (2), a lifting pulley (3) and two symmetrical and cross-hinged clamping arms (4); The first end of the clamping arm (4) is provided with a clamping palm (5) and a loose hook lifting point (6), the clamping palms (5) of the two clamping arms (4) are oppositely arranged, and the second end of the clamping arm (4) is provided with a clamping pulley (7); The rotating shaft of the lifting pulley (3) is connected with a connecting rod (8), and the connecting rod (8) is hinged with the second end of the clamping arm (4); The lifting wire rope (1) is connected with the main hook (9) of the hoisting equipment after being wound around the two clamping pulleys (7) and the lifting pulley (3). One end of the loose hook wire rope (2) is connected with the auxiliary hook (10) of the hoisting equipment, and the other end is connected with the loose hook lifting point (6).
2. The gravity clamp of claim 1, wherein, The clamping palm (5) is arranged on the clamping arm (4) through a first pin shaft (11), the two clamping arms (4) are cross-hinged through a second pin shaft (12), and the connecting rod (8) is hinged with the clamping arm (4) through a third pin shaft (13); Wherein, the distance between the first pin shaft (11) and the second pin shaft (12) in the vertical direction is L1, the distance between the second pin shaft (12) and the axis of the clamping pulley (7) in the vertical direction is L2, and the distance between the second pin shaft (12) and the third pin shaft (13) in the vertical direction is L3, L2≥2L1, L3≥1.5L1.
3. The gravity clamp of claim 2, wherein, Under the action of the lifting wire rope (1), the clamping force of the two clamping arms (4) is greater than twice the weight of the hoisted object (17).
4. The gravity clamp of claim 1, wherein, The second end of the clamping arm (4) is also provided with a guide pulley (14), and the loose hook wire rope (2) is connected with the loose hook lifting point (6) and the auxiliary hook (10) after being guided through the guide pulley (14).
5. The gravity clamp of claim 4, wherein, The distance between the axis of the guide pulley (14) and the second pin shaft (12) in the horizontal direction is less than the distance between the loose hook lifting point (6) and the second pin shaft (12) in the horizontal direction.
6. The gravity clamp of claim 4, wherein, The lifting pulley (3), the clamping pulley (7) and the guide pulley (14) are all provided with a rope protection device (15) for preventing the wire rope from coming out.
7. The gravity clamp of claim 1, wherein, The lifting pulley (3) has two pulley discs, and the two ends of the lifting wire rope (1) are connected with the main hook (9) after being guided through the two pulley discs.
8. The gravity clamp of claim 1, wherein, The surface of the clamping palm (5) is provided with transverse anti-skid grooves.
9. The gravity clamp of claim 1, wherein, The clamping arm (4) is provided with a limiting mechanism (16) for limiting the swing amplitude of the clamping palm (5).
10. The gravity clamp of claim 9, wherein, The limiting mechanism (16) comprises a limiting bolt, the limiting bolt is threadedly connected with the clamping arm (4), the clamping palm (5) is provided with an arc-shaped hole, and the limiting bolt is accommodated in the arc-shaped hole.