Locking control device for low-retraction anchor for large-diameter steel strand

Abstract

The present invention provides a locking control device for a large-diameter steel strand low-retraction anchor, which includes a reaction support that can pass through the steel strand and is sleeved outside the low-retraction anchor, a tension jack connected to the reaction support, a tool anchor connected to the tension jack and used to fix the steel strand, and a limit device arranged inside the reaction support; when the limit device is in the first gear, the limit device has a restraining effect on the movement of the anchor plate and at the same time has a limit effect on the upward movement distance of the working wedge, so that the working wedge can be disengaged from the anchor plate; when the limit device is in the second gear, the limit device can make the anchor plate move upward to lock the working wedge. The present invention adopts the process of first stretching the steel strand, then locking the working wedge, and then stretching the steel strand. The locking of the low-retraction anchor can be completed with only one tensioning. During the entire tensioning construction process, the tension jack and the reaction support are installed once, and there is no need to adjust the two, further saving time and improving work efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of prestressed construction, and particularly relates to a locking control device for a large-diameter steel strand low-retraction anchor Background Art

[0002] At present, according to a large amount of engineering experience, conventional anchors use a wedge-shaped structure to achieve self-anchoring of steel strands by a tapered anchor after prestress tensioning. To implement the basic process of prestress tensioning and locking, a limiting plate must be used to ensure sufficient space for relative slippage between the working wedge grips and the steel strands during tensioning. After reaching the design tensile force, anchoring and locking are carried out. The steel strands will also retract due to the limiting space, and the retraction amount is generally 6 mm (the length of the limiting space). Therefore, due to the fixed limiting space, the shorter the steel strand, the greater the prestress loss, especially for vertical prestress (typical short bundles), where the prestress loss is as high as over 50%. For this reason, low-retraction anchors have been developed to reduce the loss caused by the retraction of steel strands

[0003] CN217781739U discloses a secondary tensioning segmented assembly connection device for a low-retraction anchor, which is used to solve the problem that when the low-retraction anchor is used for secondary prestress tensioning of bridge anchors, the construction method of pulling the steel strands will cause the steel strand scratches to deepen or even the wedge grips to fall off. Although this patent forms a basic connection device for the second tensioning and improves the tensioning safety to a certain extent, it requires installing a tensioning jack twice, which is time-consuming, reduces work efficiency, and has a high labor intensity

[0004] CN214061283U discloses a one-time jacking reaction support device for a low-retraction anchor, which solves the problems of wedge clip retraction, controlling the slip of the prestressed tendon, and the need for secondary jacking. Although there is no need to reinstall the tensioning jack for the second tensioning, and the force-bearing structure is switched through the outer cylinder and the inner cylinder, which saves a certain amount of time, two tensioning operations are still required. Moreover, in the first tensioning of the aforementioned patent, the wedge clip is pressed into the anchor plate to fix the entire low-retraction anchor on the steel strand. In the second tensioning, the low-retraction anchor is moved away from the concrete member as a whole, and the nut is rotated to make it abut against the concrete member. However, with the deepening of the design of the vertical prestressed structure, the conventional prestressed steel strands (multiple bundles of φ15.2mm combination) are gradually optimized into large-diameter steel strands (single bundle ≥ φ21.8mm). According to the different prestress levels, the length of the steel strand stretched can reach dozens of millimeters. And because the steel strand is bent under the influence of gravity when installed in the vertical duct, there is an inelastic elongation of dozens of millimeters for the steel strand. When using the aforementioned device, during the second tensioning, as the steel strand is stretched, the upward movement distance of the low-retraction anchor will also reach more than a hundred millimeters. When the nut abuts against the concrete member, the nut will rotate downward nearly a hundred millimeters. On the one hand, it is necessary to rotate the nut dozens of times, with a large labor intensity. On the other hand, there is also a situation where it exceeds the height of the low-retraction anchor itself, and the construction is extremely unsafe. Summary of the Invention

[0005] The present invention aims to solve the technical problems existing in the prior art. The object of the present invention is to provide a locking control device for a large-diameter steel strand low-retraction anchor.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A locking control device for a large-diameter steel strand low-retraction anchor, the low-retraction anchor includes an anchor plate sleeved on the steel strand, an outer ring threadedly connected to the outer wall of the anchor plate, and working wedge clips sleeved on the steel strand and inserted into the tapered hole of the anchor plate; the locking control device includes a reaction support that can pass through the steel strand and be sleeved outside the low-retraction anchor, a tensioning jack located above and connected to the reaction support, a tool anchor connected to the upper end of the tensioning jack for fixing the steel strand, and a limiting device sleeved on the steel strand and provided inside the reaction support. The limiting device has a first gear position and a second gear position; when the limiting device is in the first gear position, the limiting device has a restraining effect on the movement of the anchor plate and at the same time has a limiting effect on the upward movement distance of the working wedge clips, so that the working wedge clips can be disengaged from the anchor plate; by operating the limiting device, the limiting device can move the anchor plate upward to lock the working wedge clips, and the limiting device is in the second gear position.

[0007] In the above technical solution, the reaction force is fixed by the tool anchor. During the tensioning process, the reaction force support is tightened against the concrete member to transfer the acting force. In the first stage of tensioning, the upward movement distance of the anchor plate and the working wedge grips is restricted by the limiting device, and the steel strand is stretched to apply the tension. When the tension reaches the designed tension (that is, when the elongation length of the steel strand in the early stage is long enough and the elongation length in the later stage is short), the anchor plate is lifted and the working wedge grips are fully locked. In the continued tensioning of the second stage, as the steel strand elongates, the entire low-retraction anchor moves upward in parallel. However, the elongation length of the steel strand in the second stage is small, so the upward movement distance of the low-retraction anchor is small. Therefore, when the outer ring abuts against the concrete member in the subsequent rotation, the number of rotations of the outer ring is small, which saves time and effort. Moreover, because the movement distance of the outer ring is small, there is no situation exceeding the height of the low-retraction anchor itself, and the construction is safer.

[0008] The present invention adopts the process of first stretching the steel strand, then locking the working wedge grips, and then stretching the steel strand. The locking of the low-retraction anchor can be completed with only one tensioning. During the entire tensioning construction process, the tensioning jack and the reaction force support are installed once, and there is no need to adjust the two, which further saves time and improves work efficiency.

[0009] In a preferred embodiment of the present invention, the limiting device includes an elastic buffer unit fixedly connected to the reaction force support, an inner cylinder fixedly connected to the lower end of the elastic buffer unit and located above the working wedge grips, and an outer cylinder movably connected to the inner cylinder and connected to the upper part of the anchor plate and capable of driving the anchor plate to move upward. When the limiting device is in the first gear position, the outer cylinder can restrict the upward movement of the anchor plate, and a limiting groove for restricting the upward movement distance of the working wedge grips is formed between the lower surface of the inner cylinder and the outer cylinder. By operating the outer cylinder, the outer cylinder can drive the anchor plate to move upward to lock the working wedge grips, and the limiting device is in the second gear position.

[0010] In the above technical solution, by setting the inner cylinder and the outer cylinder, in the tensioning construction of the first stage, the upward movement of the anchor plate is restricted by the outer cylinder, and the upward movement distance of the working wedge grips is restricted by the limiting groove formed between the inner cylinder and the outer cylinder. When the tension reaches the designed tension, the outer cylinder drives the anchor plate to move upward to lock the working wedge grips to fix the entire low-retraction anchor on the steel strand. In the tensioning construction of the second stage, the upward displacement of the steel strand and the low-retraction anchor is provided by the deformation of the elastic buffer unit to ensure the application of the tension. The structure of the limiting device of the present invention is simple and easy to operate.

[0011] In a preferred embodiment of the present invention, the elastic buffer unit is a columnar spring with the upper end fixedly connected to the reaction force support, and the upper end of the inner cylinder is fixedly connected to the lower end of the columnar spring.

[0012] In the above technical solution, the columnar spring is easy to obtain and can be made into springs with different stiffnesses according to needs to meet the use requirements.

[0013] In a preferred embodiment of the present invention, the outer cylinder is threadedly connected to the outer wall of the inner cylinder, and the outer cylinder is threadedly connected to the outer wall of the upper portion of the anchor plate, and the outer threads of the inner cylinder outer wall and the anchor plate outer wall have the same rotation direction and helix angle.

[0014] In the above technical scheme, the outer cylinder and the inner cylinder, as well as the outer cylinder and the anchor plate are connected by threaded connection, which can be self-locking. On the one hand, during the first stage of tensioning, the depth of the limit groove can be guaranteed not to change. On the other hand, when the outer cylinder is rotated, the anchor plate can also move upward to lock the working clamp. The structure is simple and the operation is convenient. Moreover, the outer cylinder and the anchor plate are threadedly connected, and only the original thread on the outer wall of the anchor plate is required. There is no need to modify the anchor plate on site, so the original structure of the anchor plate is maintained, saving the time and cost of modifying the anchor plate.

[0015] In a preferred embodiment of the present invention, a labor-saving rod for rotating the outer cylinder is connected to the side wall of the outer cylinder.

[0016] The above technical solution saves more effort by arranging a labor-saving rod and rotating the outer cylinder by holding the labor-saving rod.

[0017] In another preferred embodiment of the present invention, the locking control device also includes a plurality of torque wrenches for rotating the outer ring relative to the anchor plate. The outer wall of the reaction support is circular, and a plurality of sliders corresponding to the plurality of torque wrenches at circumferential intervals are movably connected to the outer wall of the reaction support. The torque wrenches radially pass through the sliders and the side walls of the reaction support and are threadedly connected to the sliders. By rotating the torque wrenches, the plurality of torque wrenches can move radially to hold the outer wall of the outer ring, and by operating the torque wrenches to make the sliders move circumferentially and axially on the outer wall of the reaction support, the outer ring can spirally move on the anchor plate so that its lower end is away from the lower end of the anchor plate.

[0018] The above technical solution, by setting a plurality of twist wrenches to hold the outer wall of the outer ring, and by making the twist wrenches move spirally on the reaction force bracket, the outer ring can be spirally moved to press against the concrete member, which is more labor-saving than directly holding the outer ring by hand and rotating it. After the twist wrenches are set, the outer ring and the concrete member can be more closely fitted by applying torque, reducing the retraction amount of the working clamp. In addition, by setting a plurality of twist wrenches to hold the outer wall of the outer ring, the present invention does not need to modify the anchor plate on site, maintains the original structure of the outer ring, and saves time and cost for modifying the outer ring.

[0019] In another preferred embodiment of the present invention, the outer wall of the reaction support has a spiral groove extending circumferentially and axially, the slider can move circumferentially and axially in the spiral groove, and the rotation direction and helix angle of the spiral groove are the same as the rotation direction and helix angle of the internal thread of the inner wall of the outer ring.

[0020] In the above technical solution, by providing spiral grooves to guide the circumferential and axial movements of the slider, the rotation of the outer ring becomes smoother; the spiral direction and helix angle of the spiral grooves are the same as those of the internal thread on the inner wall of the outer ring, ensuring that the outer ring and the wrench rotate and move downward synchronously in a spiral manner.

[0021] In another preferred embodiment of the present invention, the slider has a sliding post that is clamped in the spiral groove and slides therein.

[0022] In the above technical solution, by enabling the sliding post to slide in the spiral groove, the axial and circumferential movements of the slider can be achieved, further enhancing the stability of the slider movement.

[0023] In another preferred embodiment of the present invention, the slider is an arc-shaped block that extends circumferentially along the outer wall of the reaction support, and the inner surface of the arc-shaped block fits the outer surface of the side wall of the reaction support.

[0024] In the above technical solution, since the slider is an arc-shaped block, the contact area with the outer wall of the reaction support is increased, resulting in a better guiding effect and facilitating the smooth movement of the wrench when applying torque.

[0025] Additional aspects and advantages of the present invention will be partially presented in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a schematic structural diagram of the locking control device of the large-diameter steel strand low-retraction anchor in the first embodiment Figure 1 , which is a schematic diagram of the state of connection between the low-retraction anchor and the low-retraction anchor. For easy observation, the low-retraction anchor and the limiting device are shown in a sectional view.

[0028] Figure 2 is a schematic structural diagram of the locking control device of the large-diameter steel strand low-retraction anchor in the first embodiment Figure 2 , which is a state diagram before the locking control device is connected to the low-retraction anchor.

[0029] Figure 3 is a schematic structural diagram of the locking control device of the large-diameter steel strand low-retraction anchor in the first embodiment Figure 3 , which is a schematic diagram of the state where the upper end of the working jaw is in contact with the bottom of the limiting groove.

[0030] Figure 4 is a schematic structural diagram of the locking control device of the large-diameter steel strand low-retraction anchor in the first embodiment Figure 4 , which is a schematic diagram of the state where the anchor plate moves upward and locks the working jaw.

[0031] Figure 5 is a schematic structure diagram of the locking control device for the large-diameter steel strand low-retraction anchor of the first embodiment Figure 5 , which is a schematic diagram of compressing the columnar spring to make the low-retraction anchor move upward in parallel with the inner cylinder and the outer cylinder.

[0032] Figure 6 is a schematic structure diagram of the locking control device for the large-diameter steel strand low-retraction anchor of the first embodiment Figure 6 , which is a schematic diagram of the locked state of the low-retraction anchor.

[0033] Figure 7 is a schematic structure diagram of the locking control device for the large-diameter steel strand low-retraction anchor of the second embodiment.

[0034] Figure 8 is a top view cross-sectional schematic diagram of the connection between the twisting wrench and the slider and the reaction support in the second embodiment.

[0035] The reference numerals in the accompanying drawings of the specification include: steel strand 1, tool anchor 2, tensioning jack 3, reaction support 4, spiral groove 41, limit device 5, elastic buffer unit (columnar spring) 51, inner cylinder 52, outer cylinder 53, limit groove 54, labor-saving lever 55, low-retraction anchor 6, anchor plate 61, outer ring 62, working wedge 63, concrete member 7, twisting wrench 8, slider 9, sliding column 91. Specific Embodiments

[0036] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0037] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "lateral", "vertical", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0038] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "installation", "connection", and "linkage" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the communication inside two components. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0039] Embodiment 1

[0040] This embodiment provides a locking control device for a low-retraction anchor for large-diameter steel strands (hereinafter referred to as steel strands). As Figure 1 shown, among them, the low-retraction anchor 6 includes an anchor plate 61 sleeved outside the steel strand 1, an outer ring 62 threadedly connected to the outer wall of the anchor plate 61, and a working wedge 63 sleeved outside the steel strand 1 and inserted into the tapered hole of the anchor plate 61. The low-retraction anchor 6 is a prior art, and its specific structure and principle will not be described in detail here.

[0041] As Figure 1 shown, in a preferred embodiment, the locking control device of the present invention includes a reaction support 4 that can pass through the steel strand 1 and be sleeved outside the low-retraction anchor 6, a tensioning jack 3 connected to the reaction support 4 and located above it, a tool anchor 2 connected to the upper end of the tensioning jack for fixing the steel strand 1 (the structure and principle of the tool anchor 2 can adopt the prior art and are not the innovation points of the present invention, so they will not be described in detail here), and a limiting device 5 sleeved outside the steel strand 1 and arranged inside the reaction support 4 to provide reaction force fixation for the tool anchor 2 to fix the steel strand 1. The limiting device 5 has a first gear and a second gear. When the limiting device 5 is in the first gear, the limiting device 5 has a restraining effect on the anchor plate 61 to limit its upward movement, and at the same time has a limiting effect on the upward movement distance of the working wedge 63. By operating the limiting device 5, the limiting device 5 can make the anchor plate 61 move upward to lock the working wedge 63, and the limiting device 5 is in the second gear.

[0042] During use, as Figure 1 and Figure 2 shown, first install the locking control device on the already installed large-diameter steel strand 1, with the reaction support 4 against the concrete member 7, and then connect the limiting device 5 to the low-retraction anchor 6. As Figure 1 and Figure 3 shown, make the limiting device 5 in the first gear, and the tensioning jack 3 starts to work for tensioning construction. The steel strand 1 is stretched. Under the limiting action of the limiting device 5, the working wedge 63 disengages from the anchor plate 61 and moves upward. The upward movement distance of the working wedge 63 is limited by the limiting device 5 to prevent the upward movement distance of the working wedge 63 from being too large. As Figure 4As shown, when the preset tensile force is reached, operate the limiting device 5. The limiting device 5 moves the anchor plate 61 upward to fully lock the working wedge 63, fixes the anchor plate 61 and the working wedge 63 on the steel strand 1, and places the limiting device 5 in the second gear. As Figure 5 shown, the tensioning jack 3 continues to tension, and the entire low-retraction anchor 6 moves upward in parallel with the stretching of the steel strand 1. The lower end of the anchor plate 61 moves away from the concrete member 7 until the design tensile force is reached. As Figure 6 shown, rotate the outer ring 62 to make the outer ring 62 press tightly against the concrete member 7, completing the locking of the steel strand 1 by the low-retraction anchor 6. After unloading the pressure of the tensioning jack 3, remove the locking control device.

[0043] As Figure 1 shown, in the present invention, the limiting device 5 includes an elastic buffer unit 51 fixedly connected to the reaction support 4, an inner cylinder 52 fixedly connected to the lower end of the elastic buffer unit 51 and located above the working wedge 63, and an outer cylinder 53 movably connected to the inner cylinder 52 and connected to the upper part of the anchor plate 61, which can drive the anchor plate 61 to move upward. As Figure 1 shown, when the limiting device 5 is in the first gear, the outer cylinder 53 can restrict the upward movement of the anchor plate 61, and a limiting groove 54 for restricting the upward movement distance of the working wedge 63 is formed between the lower surface of the inner cylinder 52 and the outer cylinder 53 (the depth of the limiting groove 54 is generally 12 mm, matching the working wedge 63 of the large-diameter steel strand 1 with a diameter of φ21.8 mm); as Figure 3 and Figure 4 shown, by operating the outer cylinder 53, the outer cylinder 53 can drive the anchor plate 61 to move upward to lock the working wedge 63, and the lower surface of the inner cylinder 52 abuts against the upper surface of the working wedge 63. At this time, the limiting device 5 is in the second gear.

[0044] In the present invention, the elastic buffer unit 51 is a columnar spring fixedly connected to the reaction support 4 at the upper end (such as by welding or bonding with strong glue), and the upper end of the inner cylinder 52 is fixedly connected to the lower end of the columnar spring 51. The outer cylinder 53 is threadedly connected to the outer wall of the inner cylinder 52 and is connected to the external thread on the upper part of the outer wall of the anchor plate 61 (the external thread on the outer wall of the anchor plate 61 is the external thread for screwing in and out the outer ring 62, which is the existing external thread on the anchor plate 61). The external thread on the outer wall of the inner cylinder 52 has the same helix direction and helix angle as the external thread on the outer wall of the anchor plate 61; preferably, a labor-saving rod 55 for rotating it is connected to the side wall of the outer cylinder 53.

[0045] The implementation steps of the locking control device of the present invention can adopt the following process:

[0046] The first step: Prepare for the tensioning construction in the order of the design document;

[0047] Step 2: Install the locking control device of the present invention at the hole positions where the large-diameter steel strand 1 and the low-retraction anchor 6 have been set. As Figure 2 shown, before installation, a person's hand can reach into the reaction support 4 and rotate the outer cylinder 53 by operating the labor-saving lever 55 so that the lower end of the outer cylinder 53 is higher than the upper end of the inner cylinder 52. Then, when the reaction support 4 is abutted against the concrete member 7, the lower end of the outer cylinder 53 is higher than the upper end of the anchor plate 61, avoiding interference; as Figure 1 shown, then, align the center by horizontally moving the position of the reaction support 4 and rotate the outer cylinder 53 to move it downward. The outer cylinder 53 is threadedly connected to the anchor plate 61, and a limiting groove 54 for restricting the upward movement distance of the working wedge 63 is formed between the lower surface of the inner cylinder 52 and the outer cylinder 53. The limiting device 5 is in Figure 1 the first gear position as shown. During actual operation, when rotating the outer cylinder 53 to threadedly connect it to the anchor plate 61, it can be rotated until the outer cylinder 53 cannot be rotated. At this time, the step of the outer cylinder 53 abuts against the upper end surface of the anchor plate 61; of course, the step of the outer cylinder 53 may not abut against the upper end surface of the anchor plate 61, as long as there is enough screwing length between the outer cylinder 53 and the anchor plate 61.

[0048] Step 3: After meeting the tensioning conditions, start the tensioning construction and carry out the first-stage tensioning. As Figure 3 shown, the tensioning jack 3 works. When the tensile force is loaded in the range of 0 to 0.9 times the designed tensile force (0.9 times the designed tensile force is the aforementioned preset tensile force), since the outer cylinder 53 is threadedly connected to the anchor plate 61 and can be self-locked, the outer cylinder 53 has a restraining effect on the upward movement of the anchor plate 61, and the bottom of the limiting groove 54 (or the lower surface of the inner cylinder 52) has a limiting effect on the working wedge 63, which can limit the upward movement distance of the working wedge 63. The tensioning jack 3 elongates, causing the steel strand 1 to generate an upward displacement and elongation relative to the working wedge 63.

[0049] Step 4: When the tensile force reaches 0.9 times the designed tensile force, as Figure 4 shown, rotate the outer cylinder 53 by operating the labor-saving lever 55 so that the outer cylinder 53 spirally moves upward on the inner cylinder 52. Since the external threads on the outer wall of the inner cylinder 52 and the external threads on the outer wall of the anchor plate 61 have the same helix direction and helix angle, when rotating the outer cylinder 53, the outer cylinder 53 will generate an upward thrust on the anchor plate 61 through the threads, and the outer cylinder 53 drives the anchor plate 61 to move upward until the anchor plate 61 fully locks the working wedge 63, and the low-retraction anchor 6 is integrally fixed on the steel strand 1. At this time, the lower surface of the inner cylinder 52 abuts against the upper surface of the working wedge 63, and the limiting device 5 no longer provides an upward movement space for the working wedge 63. The limiting device 5 is in the second gear position, and as the anchor plate 61 moves upward, the lower end of the anchor plate 61 gradually leaves the concrete member 7.

[0050] Step 5: After the anchor plate 61 fully locks the working wedge 63, carry out the second-stage tensioning. AsFigure 5 As shown, the tensioning is from 0.9 times the design tension to 1 times the design tension. The columnar spring 51 is compressed and deformed, causing the low-retraction anchor 6 and the outer cylinder 53 and the inner cylinder 52 to move upward in parallel, and the low-retraction anchor 6 moves away from the concrete member 7. It should be noted that the stiffness of the columnar spring 51 should be selected to be large enough. Before the tension reaches 0.9 times the design tension, the compression amount of the columnar spring 51 is very small and can be basically ignored.

[0051] Step 6: When the tension applied by the tensioning jack 3 reaches the design tension, as Figure 6 shown, rotate the outer ring 62 and tighten it (specifically, the worker can put his hand into the reaction support 4 to hold the outer ring 62 and rotate it, or use the wrench 8 in Embodiment 2 to rotate it), so that the outer ring 62 abuts against the concrete member 7, and the low-retraction anchor 6 completes the locking of the steel strand 1.

[0052] Step 7: After the rotation of the outer ring 62 of the low-retraction anchor 6 is completed, unload the pressure of the tensioning jack 3 and remove the locking control device from the low-retraction anchor 6.

[0053] Embodiment 2

[0054] The structural principle of this embodiment is basically the same as that of Embodiment 1. The difference is that, as Figure 7 and Figure 8 shown, the locking control device of this embodiment further includes a plurality of wrenches 8 for rotating the outer ring 62 relative to the anchor plate 61. The outer wall of the lower part of the reaction support 4 is circular, and a plurality of sliders 9 corresponding to the plurality of wrenches 8 at intervals in the circumferential direction are movably connected to the outer wall of the reaction support 4. The wrench 8 radially passes through the slider 9 and the side wall of the reaction support 4 and is threadedly connected to the slider 9.

[0055] In this embodiment, the outer wall of the reaction support 4 has a spiral groove 41 extending in the circumferential and axial directions. The slider 9 can move in the circumferential and axial directions in the spiral groove 41. For example, the slider 9 has a sliding column 91 clamped in the spiral groove 41 and sliding therein. The spiral direction and spiral angle of the spiral groove 41 are the same as those of the internal thread on the inner wall of the outer ring 62. Preferably, the slider 9 is an arc-shaped block extending in the circumferential direction of the outer wall of the reaction support 4, and the inner surface of the arc-shaped block fits the outer surface of the side wall of the reaction support 4.

[0056] In the normal state, the wrench 8 is threadedly connected to the slider 9, passes through the reaction support 4, and is away from the outer wall of the outer ring 62, without affecting the tensioning construction. When rotating the outer ring 62 and tightening it in the aforementioned sixth step, the wrench 8 can be rotated self - rotatably, and the wrench 8 moves radially. The length of the wrench 8 extending into the reaction support 4 becomes longer and contacts the outer wall of the outer ring 62. Tighten all the wrenches 8, and multiple wrenches 8 hold the outer wall of the outer ring 62 tightly. After holding the outer ring 62 tightly, apply torque by operating the wrench 8. Under the guiding action of the spiral groove 41, the slider 9 moves circumferentially and axially (spirally downward) on the outer wall of the reaction support 4. Since the helix direction and helix angle of the spiral groove 41 are the same as those of the internal thread on the inner wall of the outer ring 62, and their pitches are also equal, the outer ring 62 and the wrench 8 move spirally downward synchronously. The lower end of the outer ring 62 moves away from the lower end of the anchor plate 61 and approaches the concrete member 7, and the lower end of the outer ring 62 is pressed tightly against the concrete member 7.

[0057] When it is necessary to rotate the outer ring 62 for multiple turns, the wrench 8 can be loosened to release the outer ring 62. After the torque wrench and the slider 9 move in the reverse direction and reset, then tighten the torque wrench to hold the outer ring 62 tightly, and then operate the wrench 8 to rotate the outer ring 62 until the outer ring 62 abuts against the concrete member 7 and the torque wrench cannot rotate anymore, so as to ensure the locking effect of the outer ring 62 and reduce the retraction amount of the working wedge 63. Of course, it is also possible to first rotate the outer ring 62 manually to make it move downward to contact the concrete member 7, and then use multiple torque wrenches to hold the outer ring 62 tightly and apply torque for fastening.

[0058] Figure 8 As shown, two wrenches 8 are arranged circumferentially. According to the actual situation, to ensure that multiple wrenches 8 can hold the outer ring 62 tightly, three or more wrenches 8 can be arranged. Preferably, the end of the wrench 8 has an anti - slip pad, and the shape of the anti - slip pad is an arc adapted to the outer wall of the outer ring 62, so that the holding effect is better.

[0059] In the description of this specification, the description referring to terms such as "preferred embodiment", "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above - mentioned terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0060] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. Locking control device for large-diameter steel strand low-retraction anchor, the low-retraction anchor comprising an anchor plate sleeved outside the steel strand, an outer ring threadedly connected to the outer wall of the anchor plate, and a working wedge inserted outside the steel strand and into the tapered hole of the anchor plate; characterized in that, The locking control device includes a reaction support capable of passing through the steel strand and sleeving outside the low-retraction anchor, a tension jack located above and connected to the reaction support, a tool anchor connected to the upper end of the tension jack for fixing the steel strand, and a limiting device disposed within the reaction support and sleeving outside the steel strand. The limiting device has a first gear position and a second gear position; When the limiting device is in the first gear position, the limiting device has a constraining effect on the movement of the anchor plate and at the same time has a limiting effect on the upward movement distance of the working wedge, so that the working wedge can be disengaged from the anchor plate; By operating the limiting device, the limiting device can move the anchor plate upward to lock the working wedge, and the limiting device is in the second gear position; the limiting device includes an elastic buffer unit fixedly connected to the reaction support, an inner cylinder located above the working wedge and fixedly connected to the lower end of the elastic buffer unit, and an outer cylinder movably connected to the inner cylinder and connected to the upper part of the anchor plate and capable of driving the anchor plate to move upward; When the limiting device is in the first gear position, the outer cylinder can constrain the upward movement of the anchor plate, and a limiting groove for restricting the upward movement distance of the working wedge is formed between the lower surface of the inner cylinder and the outer cylinder; By operating the outer cylinder, the outer cylinder can drive the anchor plate to move upward to lock the working wedge, and the limiting device is in the second gear position; The outer cylinder is threadedly connected to the outer wall of the inner cylinder, and the outer cylinder is threadedly connected to the outer thread on the upper outer wall of the anchor plate. The helix directions and helix angles of the outer thread on the outer wall of the inner cylinder and the outer thread on the outer wall of the anchor plate are the same.

2. The locking control device of the large-diameter steel strand low-retraction anchor according to claim 1, characterized in that, The elastic buffer unit is a columnar spring with its upper end fixedly connected to the reaction support, and the upper end of the inner cylinder is fixedly connected to the lower end of the columnar spring.

3. The locking control device of the large-diameter steel strand low-retraction anchor according to claim 1, characterized in that, A labor-saving rod for rotating the outer cylinder is connected to the side wall of the outer cylinder.

4. The locking control device of the large-diameter steel strand low-retraction anchor according to any one of claims 1-3, characterized in that, It further includes a plurality of twisting wrenches for rotating the outer ring relative to the anchor plate. The outer wall of the reaction support is circular, and a plurality of sliders circumferentially spaced and corresponding to the plurality of twisting wrenches one by one are movably connected to the outer wall of the reaction support. The twisting wrench radially passes through the slider and the side wall of the reaction support and is threadedly connected to the slider; By rotating the twisting wrench, the plurality of twisting wrenches can move radially to clamp the outer wall of the outer ring. By operating the twisting wrench, the slider moves circumferentially and axially on the outer wall of the reaction support, and the outer ring can perform a spiral movement on the anchor plate to make the lower end thereof away from the lower end of the anchor plate.

5. The locking control device of the large-diameter steel strand low-retraction anchor according to claim 4, characterized in that, The outer wall of the reaction support has a spiral groove extending circumferentially and axially. The slider can move circumferentially and axially in the spiral groove. The helix direction and helix angle of the spiral groove are the same as the helix direction and helix angle of the internal thread on the inner wall of the outer ring.

6. The locking control device of the large-diameter steel strand low-retraction anchor described in claim 5, characterized in that, The slider has a sliding column clamped in the spiral groove and sliding therein.

7. The locking control device of the large-diameter steel strand low-retraction anchor according to claim 5, characterized in that, The slider is an arc-shaped block extending circumferentially along the outer wall of the reaction support, and the inner surface of the arc-shaped block fits the outer surface of the side wall of the reaction support.

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