Rapid anti-torsion device for sling tensioning

Abstract

The invention relates to a quick anti-torsion device for sling tensioning, and belongs to the technical field of sling tensioning. The anti-torsion device is arranged on the outer side of a tension pull rod, the end of the pull rod is fixedly connected with an anchor cup at the end of a sling, the anti-torsion device comprises an anti-torsion wrench, a fixed support and a movable support, the movable support and the fixed support are movably connected, and the relative distance between the movable support and the fixed support can be adjusted. The jaw of the anti-torsion wrench clamps the pull rod, the end of the anti-torsion wrench abuts against the movable support, and the movable support limits rotation of the anti-torsion wrench. The device is simple in structure and convenient to operate, torsion can be avoided when the sling is installed and tensioned, the sling is evenly stressed after a bridge is formed, and safety is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a torsion prevention device for a sling. BACKGROUND

[0002] Steel wire rope sling is usually made of a plurality of steel wires twisted into strands, and the small-pitch galvanized steel wire rope is twisted into a plurality of layers of the steel wires inside and outside the strands, and has a small elastic modulus. When the sling is tensioned, the sling may be twisted to different degrees under the axial force, and the twisting of the sling end may affect the length of the sling, and further cause uneven stress of the sling after the bridge is completed. The twisting of the sling during tensioning is one of the technical problems to be solved by those skilled in the art. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a quick torsion prevention device for a boom tensioning, which is simple in structure, convenient to operate, can avoid the twisting of the sling during the tensioning of the sling, avoid the length change of the sling, especially the end, ensure the uniform stress of the sling after the bridge is completed, and improve the safety of the bridge.

[0004] The technical scheme adopted by the present application to solve the above problems is: a quick torsion prevention device for a sling tensioning is arranged on the outer side of a tensioning pull rod, the end of the pull rod is fixedly connected with an anchor cup at the end of the sling, and the device is characterized in that: it comprises a torsion prevention wrench, a fixed support and a movable support, the movable support is movably connected with the fixed support and the relative distance between them is adjustable, the tiger mouth of the torsion prevention wrench clamps the pull rod, and the end of the torsion prevention wrench abuts against the movable support, and the movable support forms a limit for the rotation of the torsion prevention wrench.

[0005] As one of the embodiments, a clamping groove is formed on the surface of the pull rod, and the tiger mouth of the torsion prevention wrench clamps the clamping groove, and a plurality of clamping grooves are distributed in a ring shape.

[0006] As one of the embodiments, a wrench limiting groove is arranged on the movable support, and the end of the torsion prevention wrench is clamped in the wrench limiting groove.

[0007] As one of the embodiments, a connecting hole is formed on the fixed support and the movable support respectively, and a connecting piece is locked into the connecting holes of the fixed support and the movable support to movably connect the fixed support and the movable support and adjust the relative position. The connecting piece is an adjusting bolt, and the connecting hole is a threaded hole. The adjusting bolt adjusts the distance between the movable support and the fixed support.

[0008] The torsion prevention wrench must meet strict design standards. The force transmission path of the mechanism is: the torque of the steel wire rope sling is transmitted to the pull rod, and then transmitted to the torsion prevention wrench by the pull rod. Specifically, the strength calculation of the torsion prevention wrench aims to accurately evaluate the load capacity of the transition area (stress concentration area) of the wrench between the handle and the tiger mouth, that is, by analyzing the bending moment of the key stress section, the structural reliability is verified.

[0009] The sling wire rope is generally selected to have an IWS structure, and a nominal diameter of D. The diameter of the innermost layer of wire strands is d1, and the wire strands are sequentially divided into n layers from the inside to the outside, and the diameter of the wire strands of the i-th layer is di i The number of the wire strands of the i-th layer is n i ,

[0010] The torque calculation formula of the sling wire rope is:

[0011]

[0012] In the formula, M represents the torque of the sling wire rope (unit: NM);

[0013] n represents the number of layers of the wire strands;

[0014] F i represents the axial force of the wire strands of the i-th layer (unit: kN);

[0015] D i represents the center diameter of the wire strands of the i-th layer (unit: mm);

[0016] H represents the lay length of the wire rope (unit: mm), which is generally m times of the nominal diameter of the wire rope, H = mD.

[0017]

[0018] In the formula, F represents the tension of the sling wire rope (unit: kN);

[0019] A i represents the cross-sectional area of the wire strands of the i-th layer (unit: mm 2 );

[0020] A represents the cross-sectional area of the sling wire rope.

[0021]

[0022] In the formula, n i represents the number of the wire strands of the i-th layer;

[0023] d i represents the diameter of the wire strands of the i-th layer (unit: mm).

[0024] When i = n, D n = D-d n (5) when i < n,

[0025] In the formula, D represents the nominal diameter of the wire rope (unit: mm);

[0026] d j represents the diameter of the wire strands of the j-th layer (unit: mm).

[0027] The reaction torque of the open end of the wrench is the maximum torque generated by each layer of steel wire of the steel wire rope. The cross-sectional geometric parameters of the transition area between the handle and the open end of the anti-twist wrench are known: the cross-sectional width b (in the force direction); the cross-sectional height h.

[0028] The cross-sectional bending modulus Z:

[0029]

[0030] The bending stress σ of the anti-twist wrench b :

[0031]

[0032] When , the wrench meets the use requirements, σ y is the material yield strength, and n is the safety factor, usually 2-4.

[0033] Compared with the prior art, the advantages of the present application are that: a hanging rod tensioning rapid anti-twist device, the anti-twist wrench interacts with the groove when subjected to force, avoiding the occurrence of twisting when the sling is tensioned. The present application has the advantages of simple structure, convenient operation, and can avoid twisting when the sling is installed and tensioned, so that the sling is uniformly stressed after the bridge is formed, and the safety is improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a schematic diagram of the sling tensioning anti-twist operation in the embodiment of the present application;

[0035] Figure 2 It is a longitudinal sectional view of the anti-twist device;

[0036] Figure 3 It is a transverse sectional view of the anti-twist device;

[0037] Figure 4 It is a structural schematic diagram of the fixed support;

[0038] Figure 5 It is a structural schematic diagram of the movable support;

[0039] Figure 6 It is a structural schematic diagram of the pull rod;

[0040] Figure 7 It is Figure 6 the BB sectional view;

[0041] In the figure, 1 is a steel wire rope sling, 2 is an anchor cup, 3 is a connecting sleeve, 4 is a pull rod, 4.1 is a clamping groove, 5 is an anti-twist device, 5.1 is a fixed support, 5.2 is a movable support, 5.3 is an adjusting bolt, 5.4 is an anti-twist wrench, and 5.5 is a wrench limiting groove. DETAILED DESCRIPTION

[0042] The present application is further described in detail below with reference to the accompanying drawings, which are exemplary and intended to provide an explanation of the present application and are not intended to limit the scope of the present application. The description in the present embodiment is corresponding to the drawings, and the description of the orientation is also based on the description of the drawings, which should not be understood as limiting the scope of the present application.

[0043] In the present embodiment, one kind of derrick tensioning quick anti-twist device, one end of the steel wire rope sling is provided with an anchor cup 2, the dispersed steel wires are anchored in the anchor cup 2, the tail of the anchor cup 2 is provided with a connecting sleeve 3, the connecting sleeve 3 is threadedly connected with a pull rod 4, and the steel wire rope sling is tensioned through the pull rod 4. An anti-twist device 5 is installed on the outer side of the pull rod 4, a plurality of circumferentially symmetrical and uniformly distributed clamping grooves 4.1 are formed on the outer periphery of the pull rod 4, the anti-twist wrench is matched with the clamping grooves 4.1, the anti-twist wrench 5.4 is clamped to the pull rod, the pull rod 4 is limited, and the twisting of the sling during tensioning is avoided.

[0044] As shown in Figures 2-7 The anti-twist device includes a fixed support 5.1 and a movable support 5.2 which is oppositely arranged with the fixed support 5.1, a wrench limiting groove 5.5 is formed on the movable support 5.2, and the handle end of the anti-twist wrench 5.4 is clamped inside the wrench limiting groove 5.5. Two vertically spaced screw holes are formed on the fixed support 5.1, and two screw holes are correspondingly arranged on the movable support 5.2. The adjusting bolt 5.3 is screwed in the screw holes corresponding to each other of the fixed support and the movable support. The adjusting bolt can adjust the relative distance between the fixed support and the movable support to adapt to the steel wire rope sling at different positions.

[0045] The width of the tiger mouth of the anti-twist wrench 5.4 is matched with the symmetrical clamping grooves 4.1, so that the anti-twist wrench 5.4 can just clamp the pull rod 4.

[0046] Taking a double-layer steel wire rope sling as an example, it is known that the strands of the steel wire rope sling are sequentially divided into two layers from inside to outside. The single strand diameter of the first layer steel wire is 10 mm, the diameter of the first layer strand is 30 mm, and the corresponding number of steel wire strands is 8 strands; the single strand diameter of the second layer steel wire is 16 mm, the diameter of the second layer strand is 52 mm, and the corresponding number of steel wire strands is also 8 strands. The lay length of the steel wire rope is 8 times the nominal diameter, that is, 416 mm, and the tensioning force is 100 kN.

[0047] Based on the above calculation process, it can be obtained that:

[0048] The axial force F1 of the first layer steel wire strand is calculated by formula (2) combined with the total tension and the number of strands. Assuming that the total tension is evenly distributed to each layer of steel wire strands, F1=F×(a1 / A)=29.59 kN, wherein a1 is the cross-sectional area of the first layer single strand (π×(10 / 2) 2), A is the total cross-sectional area (the sum of the cross-sectional area of the two layers), n1 = 1 strand; similarly, the axial force of the second layer F2 = 75.74 kN is calculated. Substituting the torque formula (1) gives: where D1 = 20 mm (the diameter of the center of the first layer), D2 = 52-16 = 36 mm (the diameter of the center of the second layer); finally, M = 415.13 Nm is calculated. The material of the anti-torque wrench is Q345 steel, the yield strength σy = 325 MPa, and the safety factor n = 4, so the allowable bending stress [σ] = σy / n = 81.25 MPa. According to the cross-sectional parameters of the wrench (assuming b = 50 mm, h = 35 mm), the cross-sectional bending modulus Z = b x h 2 / 6 = 10208.33 mm 3 , and the bending stress formula (8) σ = M / Z is substituted to verify that σ ≤ [σ], i.e., the strength requirement is met. In terms of specifications, the width of the anti-torque wrench's tiger mouth needs to match the spacing of the pull rod's clamping slots (for example, if the clamping slots are arranged at an interval of 90° in a ring, the tiger mouth opening angle ≥ 90°), the handle length is designed to be 200 mm according to the operation space, and the distance between the force point and the tiger mouth axis is ensured to meet the torque requirement (torque = force x handle length ≥ calculated torque M).

[0049] In addition to the above embodiments, the present application also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement shall fall within the protection scope of the claims of the present application.

Claims

1. A rapid anti-torsion device for sling tensioning, disposed on the outside of a tensioning rod, wherein the end of the rod is fixedly connected to an anchor cup at the end of the sling, characterized in that: It includes an anti-torsion wrench, a fixed support, and a movable support. The movable support is movably connected to the fixed support and the relative distance between them is adjustable. The anti-torsion wrench has its gripping opening holding the pull rod and its end abutting against the movable support. The movable support forms a limit on the rotation of the anti-torsion wrench.

2. The rapid anti-torsion device for sling tensioning according to claim 1, characterized in that: The surface of the pull rod has a groove, and the thumb and forefinger of the anti-torsion wrench locks into the groove.

3. The rapid anti-torsion device for sling tensioning according to claim 1, characterized in that: The movable support is provided with a wrench limiting groove, and the end of the anti-torsion wrench is locked in the wrench limiting groove.

4. The rapid anti-torsion device for sling tensioning according to claim 1, characterized in that: The fixed support and the movable support are respectively provided with connection holes. The connector is simultaneously locked into the connection holes of the fixed support and the movable support so that the two are movably connected and their relative positions are adjustable.

5. The rapid anti-torsion device for sling tensioning according to claim 1, characterized in that: The anti-torsion wrench should meet the requirement that the load-bearing capacity of the transition area between the handle and the web of the hand is greater than the maximum torque generated by each layer of steel wire in the wire rope. The cross-sectional geometric parameters of the transition area between the handle and the web of the anti-torsion wrench are: cross-sectional width b and cross-sectional height h along the direction of force. Section flexural modulus Z: Bending stress σ of anti-torsion wrench b : M represents the torque of the sling wire rope, measured in Nm (m). max The maximum torque of the sling wire rope, expressed in Nm; when At that time, the wrench meets the usage requirements, σ y To prevent the twisting wrench material from yielding, n is a safety factor, ranging from 2 to 4.

6. The rapid anti-torsion device for sling tensioning according to claim 5, characterized in that: The calculation method for the torque M of the sling wire rope is as follows: Where: n — number of strands in the wire rope; F i —Axial force of the i-th layer of wire rope strand, unit: kN; D i —Center diameter of the i-th layer of wire rope strands, unit: mm; H—the lay pitch of the wire rope, in mm, is m times the nominal diameter D of the wire rope, H = mD; Where: F—tension force of the sling wire rope, unit: kN; A i —Cross-sectional area of ​​the i-th layer of steel wire rope strands, unit: mm 2 ; A – Cross-sectional area of ​​the sling wire rope; Where: n i —The number of wire rope strands corresponding to layer i; d i — Corresponding to the diameter of the wire rope strand in layer i, unit: mm; When i = n, D n =Dd n ; When i<n, In the formula: D—nominal diameter of the wire rope, unit: mm; d j — Corresponding to the diameter of the steel wire rope strand in layer j, unit: mm.

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