Locking control device of large-diameter steel strand low-retraction anchorage device

Abstract

The invention provides a locking control device of a large-diameter steel strand low-retraction anchorage device. The locking control device comprises a counter-force support, a tensioning jack, a tool anchor and a limiting device, wherein the counter-force support can penetrate through a steel strand and is arranged outside the low-retraction anchorage device in a sleeving manner; the tensioning jack is connected with the counter-force support; when the limiting device is located at the first gear, the limiting device has a restraining effect on movement of the anchor plate and meanwhile has a limiting effect on the upward moving distance of the working clamping piece, so that the working clamping piece can be separated from the anchor plate. And when the limiting device is located at the second gear, the limiting device can enable the anchor plate to move upwards, so that the anchor plate locks the working clamping piece. The technology that the steel strand is stretched firstly, then the working clamping piece is locked, and then the steel strand is stretched is adopted, locking of the low-retraction anchorage device can be completed only through one-time stretching, in the whole stretching construction process, the stretching jack and the counter-force support are installed at a time and do not need to be adjusted, time is further saved, and working efficiency is improved.

Description

Technical Field

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

[0002] At present, according to a large amount of engineering experience, conventional anchors use wedge-shaped structures to achieve the self-anchoring of the prestressed conical anchor to the steel strand. In order to realize the basic process of prestressed tensioning and locking, it is necessary to match the limit plate to ensure that there is sufficient space for the working clip and the steel strand to produce relative sliding during the tensioning process. After reaching the designed tensioning force, the anchor is locked. The steel strand will also shrink due to the limited space, and the shrinkage is generally 6mm (the length of the limited space). Therefore, since the limited space is certain, the shorter the steel strand, the greater the prestress loss, especially the prestress loss caused by vertical prestressing (typical short beam) is as high as more than 50%. For this reason, low-shrinkage anchors have been developed to reduce the losses caused by the shrinkage of the steel strand.

[0003] CN217781739U discloses a low-retraction anchor secondary tensioning segmented assembly connection device, which is used to solve the problem that the construction method of pulling the steel strand during the secondary prestressing of the bridge anchor will cause the steel strand to be scored deeper and even the clip to fall off. Although this patent forms a basic connection device for the second tensioning, which has a certain improvement in tensioning safety, it requires the installation of tensioning jacks twice, which is time-consuming, reduces work efficiency, and has a high labor intensity.

[0004] CN214061283U discloses a low-retraction anchorage one-time top-loading anti-support device, which solves the problem of clip retraction, controlling the slippage of prestressed beams, and requiring secondary top-loading. Although the tensioning jack does not need to be reinstalled for the second tensioning, the force-bearing structure is switched by the outer tube and the inner tube, which saves time, but two tensioning operations are still required. Moreover, the first tensioning of the aforementioned patent is to press the clip into the anchor plate to fix the entire low-retraction anchor on the steel strand. The second tensioning makes the low-retraction anchor as a whole away from the concrete member, and the nut is rotated to make it press against the concrete member. However, with the deepening of the design of the vertical prestressed structure, the conventional prestressed steel strand (multiple bundles of φ15.2mm combination) is gradually optimized to a large-diameter steel strand (single bundle ≥φ21.8mm). Depending on the size of the prestress, the length of the steel strand stretched can reach tens of millimeters, and because the steel strand is bent due to the influence of gravity when it is installed in the vertical channel, the steel strand has an inelastic elongation of tens of millimeters. With the aforementioned device, during the second tensioning, as the steel strand is stretched, the low-retraction anchor will move upward by hundreds of millimeters. When the rotating nut is pressed against the concrete member, the nut will rotate downward by nearly 100 millimeters. On the one hand, the nut needs to be rotated dozens of times, which is labor-intensive. On the other hand, there is also a situation where the height exceeds 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, and the purpose of the present invention is to provide a locking control device for a low-retraction anchor of a large-diameter steel strand.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a locking control device for a low-retraction anchor of a large-diameter steel strand, 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 clip sleeved outside the steel strand and inserted into a tapered hole of the anchor plate; the locking control device comprises a reaction support that can pass through the steel strand and sleeved outside the low-retraction anchor, a tensioning jack connected to the reaction support and located above the reaction support, a tool anchor for fixing the steel strand connected to the upper end of the tensioning jack, and a limiting device sleeved outside the steel strand arranged in the reaction support, the limiting device having a first gear and a second gear; when the limiting device is in the first gear, the limiting device has a restraining effect on the movement of the anchor plate and a limiting effect on the upward movement distance of the working clip, so that the working clip can be detached from the anchor plate; by operating the limiting device, the limiting device can cause the anchor plate to move upward so that the anchor plate locks the working clip, and the limiting device is in the second gear.

[0007] The above technical scheme uses tool anchors to perform reaction force fixation. During the tensioning process, the reaction force bracket is pressed against the concrete member to transmit the force. The first stage of tensioning is to limit the rising distance of the anchor plate and the working clip by the limit device, and the steel strand is stretched to apply tensioning force. When the tensioning is to the designed tensioning force (that is, the length of the steel strand stretched in the early stage is long enough and the length of the steel strand stretched in the later stage is shorter), the anchor plate rises and fully locks the working clip. In the second stage of continued tensioning, as the steel strand stretches, the entire low retraction anchor moves upward in parallel, but the length of the steel strand stretching in the second stage is shorter, so that the low retraction anchor moves up a shorter distance. Therefore, when the outer ring is rotated later to press against the concrete member, the outer ring rotates fewer times, saving time and effort. Moreover, since the distance moved by the outer ring is small, there is no situation where the height of the low retraction anchor itself is exceeded, and the construction is safer.

[0008] The present invention adopts the process of first stretching the steel strand, then locking the working clip, 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 bracket are installed at one time without the 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 fixed to the reaction force support, an inner cylinder fixed to the lower end of the elastic buffer unit and located above the working clamp, 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, the outer cylinder can constrain the anchor plate to move upward, and a limiting groove for limiting the upward movement distance of the working clamp 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 so that the anchor plate locks the working clamp, and the limiting device is in the second gear.

[0010] The above technical solution, by setting the inner tube and the outer tube, in the first stage of tensioning construction, the outer tube limits the upward movement of the anchor plate, and the limit groove formed between the inner tube and the outer tube limits the upward movement distance of the working clip. When tensioning to the designed tensioning force, the outer tube drives the anchor plate to move upward so that the anchor plate locks the working clip to fix the entire low-retraction anchor on the steel strand; in the second stage of tensioning construction, the deformation of the elastic buffer unit provides the upward displacement of the steel strand and the low-retraction anchor to ensure the application of the tensioning force. The limit device of the present invention has a simple structure and is easy to operate.

[0011] In a preferred embodiment of the present invention, the elastic buffer unit is a columnar spring whose upper end is fixed to the reaction force bracket, and the upper end of the inner cylinder is fixed 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 as needed to meet usage 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] The above technical solution guides the circumferential and axial movement of the slider by setting a spiral groove, so that the rotation of the outer ring is smoother; the rotation direction and helix angle of the spiral groove are the same as the rotation direction and helix angle of the internal thread on the inner wall of the outer ring, keeping the outer ring and the torque wrench moving downward in a synchronous spiral.

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

[0022] The above technical solution can make the slider move axially and axially by making the slide post slide in the spiral groove, further improving the stability of the slider movement.

[0023] In another preferred embodiment of the present invention, the sliding block is an arc-shaped block extending circumferentially along the outer wall of the reaction support, and the inner surface of the arc-shaped block is in contact with the outer surface of the side wall of the reaction support.

[0024] In the above technical solution, the slider is an arc-shaped block, which increases its contact area with the outer wall of the reaction support, has a better guiding effect, and is conducive to the smooth movement of the twist wrench when applying torque.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through 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 easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0027] Figure 1 The structure diagram of the locking control device of the large diameter steel strand low retraction anchor of the first embodiment is as follows Figure 1 , which is a schematic diagram of the connection between low retraction anchors. For easy observation, the low retraction anchor and the limiting device are shown in cross-section.

[0028] Figure 2 The structure diagram of the locking control device of the large diameter steel strand low retraction anchor of the first embodiment is as follows Figure 2 , which is a state diagram of the locking control device before it is connected to the low retraction anchor.

[0029] Figure 3 The structure diagram of the locking control device of the large diameter steel strand low retraction anchor of the first embodiment is as follows Figure 3 , which is a schematic diagram of the state where the upper end of the working clamp abuts against the bottom of the limiting groove.

[0030] Figure 4 The structure diagram of the locking control device of the large diameter steel strand low retraction anchor of the first embodiment is as follows Figure 4 , which is a schematic diagram of the state in which the anchor plate moves upward and locks the working clamp.

[0031] Figure 5 The structure diagram of the locking control device of the large diameter steel strand low retraction anchor of the first embodiment is as follows 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 tube and the outer tube.

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

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

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

[0035] The figure marks in the drawings of the specification include: steel strand 1, tool anchor 2, tensioning jack 3, reaction bracket 4, spiral groove 41, limit device 5, elastic buffer unit (column spring) 51, inner tube 52, outer tube 53, limit groove 54, force-saving rod 55, low retraction anchor 6, anchor plate 61, outer ring 62, working clip 63, concrete member 7, torque wrench 8, slider 9, sliding column 91. DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0037] In the description of the present invention, it is to be understood that the terms “longitudinal”, “lateral”, “vertical”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside” etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 understood as a limitation on the present invention.

[0038] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0039] Embodiment 1

[0040] This embodiment provides a locking control device for a low-retraction anchor of a large-diameter steel strand (referred to as steel strand). Figure 1 As shown, the low retraction anchor 6 includes an anchor plate 61 sleeved on the outside of the steel strand 1, an outer ring 62 threadedly connected to the outer wall of the anchor plate 61, and a working clip 63 sleeved on the outside of 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 the specific structure and principle are not described in detail here.

[0041] like Figure 1 As shown, in a preferred embodiment, the locking control device of the present invention comprises a reaction support 4 that can pass through the steel strand 1 and is 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 existing technology, which is not the innovation of the present invention and will not be described in detail here), and a limiting device 5 arranged in the reaction support 4 and sleeved outside the steel strand 1, which provides the tool anchor 2 with the reaction force 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 clamp 63. By operating the limiting device 5, the limiting device 5 can make the anchor plate 61 move upward so that the anchor plate 61 locks the working clamp 63, and the limiting device 5 is in the second gear.

[0042] When using, Figure 1 and Figure 2 As shown, the locking control device is first installed on the large-diameter steel strand 1, the reaction support 4 is supported on the concrete member 7, and then the limit device 5 is connected to the low-retraction anchor 6. Figure 1 and Figure 3 As shown, the limit device 5 is in the first gear position, the tensioning jack 3 starts to work and the steel strand 1 is stretched. Under the limiting effect of the limit device 5, the working clip 63 is separated from the anchor plate 61 and moves upward. The upward movement distance of the working clip 63 is limited by the limit device 5 to prevent the working clip 63 from moving too far upward. Figure 4As shown, when the preset tension force is reached, the limit device 5 is operated, and the limit device 5 moves the anchor plate 61 upward so that the anchor plate 61 fully locks the working clamp 63, fixes the anchor plate 61 and the working clamp 63 on the steel strand 1, and puts the limit device 5 in the second gear. Figure 5 As shown, the tensioning jack 3 continues to tension the entire low retraction anchor 6 and moves upward in parallel with the stretching of the steel strand 1, and the lower end of the anchor plate 61 is away from the concrete member 7 until the designed tensioning force is reached. Figure 6 As shown, the outer ring 62 is rotated to make the outer ring 62 press against the concrete member 7, thereby completing the locking of the steel strand 1 by the low retraction anchor 6. After unloading the pressure of the tensioning jack 3, the locking control device is removed.

[0043] like Figure 1 As shown, in the present invention, the limiting device 5 includes an elastic buffer unit 51 fixed to the reaction support 4, an inner cylinder 52 fixed to the lower end of the elastic buffer unit 51 and located above the working clamp 63, and an outer cylinder 53 movably connected to the inner cylinder 52 and connected to the upper part of the anchor plate 61 and capable of driving the anchor plate 61 to move upward. Figure 1 As shown, when the limiting device 5 is in the first gear, the outer cylinder 53 can constrain the upward movement of the anchor plate 61, and a limiting groove 54 is formed between the lower surface of the inner cylinder 52 and the outer cylinder 53 to limit the upward movement distance of the working clamp 63 (the depth of the limiting groove 54 is generally 12mm, matching the working clamp 63 of the large diameter steel strand 1 of φ21.8mm); Figure 3 and Figure 4 As shown, by operating the outer cylinder 53, the outer cylinder 53 can drive the anchor plate 61 to move upward so that the anchor plate 61 locks the working clamp 63, and the lower surface of the inner cylinder 52 abuts against the upper surface of the working clamp 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 whose upper end is fixed to the reaction support 4 (for example, by welding or strong glue), and the upper end of the inner cylinder 52 is fixed 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 the outer cylinder 53 is connected to the external thread of the upper outer wall of the anchor plate 61 (the external thread of the outer wall of the anchor plate 61 is the external thread that is screwed in and out of the outer ring 62, and is the external thread already on the anchor plate 61), and the external thread of the outer wall of the inner cylinder 52 has the same direction of rotation and helix angle as the external thread of the outer wall of the anchor plate 61; preferably, a labor-saving rod 55 for rotating the outer cylinder 53 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 be implemented in the following process:

[0046] Step 1: Prepare for tensioning construction according to the order of design documents;

[0047] Step 2: Install the locking control device of the present invention on the hole where the large diameter steel strand 1 and the low retraction anchor 6 are installed. Figure 2 As shown, before installation, people can put their hands into the reaction support 4 and rotate the outer cylinder 53 by operating the labor-saving rod 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 placed on the concrete member 7, the lower end of the outer cylinder 53 is higher than the upper end of the anchor plate 61 to avoid interference. Figure 1 As shown, the reaction support 4 is then moved horizontally to be centered, and the outer cylinder 53 is rotated to move downward. The outer cylinder 53 is threadedly connected to the anchor plate 61, and a limiting groove 54 is formed between the lower surface of the inner cylinder 52 and the outer cylinder 53 to limit the upward movement distance of the working clamp 63. The limiting device 5 is in Figure 1 In actual operation, when the outer cylinder 53 is rotated to be threadedly connected with the anchor plate 61, it can be rotated until the outer cylinder 53 cannot rotate anymore, at which 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 the outer cylinder 53 and the anchor plate 61 have a sufficient screwing length.

[0048] Step 3: Start the tensioning construction after the tensioning conditions are met, and carry out the first stage of tensioning, such as Figure 3 As shown, the tensioning jack 3 is working. When the tensioning force is between 0 and 0.9 times of the design tensioning force (0.9 times of the design tensioning force is the aforementioned preset tensioning force) during loading, since the outer cylinder 53 is threadedly connected to the anchor plate 61 and can be self-locking, 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 clamp 63, which can limit the upward movement distance of the working clamp 63. The tensioning jack 3 is extended to cause the steel strand 1 to move upward and extend relative to the working clamp 63.

[0049] Step 4: When the tension reaches 0.9 times the design tension, Figure 4 As shown, the outer cylinder 53 is rotated by the force-saving rod 55 to make the outer cylinder 53 move upward in a spiral on the inner cylinder 52. Since the external thread on the outer wall of the inner cylinder 52 and the external thread on the outer wall of the anchor plate 61 have the same rotation direction and spiral angle, when the outer cylinder 53 is rotated, the outer cylinder 53 will generate an upward thrust on the anchor plate 61 through the thread, and the anchor plate 61 is driven by the outer cylinder 53 to move upward until the anchor plate 61 fully locks the working clamp 63, and the low retraction anchor 6 is fixed on the steel strand 1 as a whole. At this time, the lower surface of the inner cylinder 52 abuts against the upper surface of the working clamp 63, and the limiting device 5 no longer provides upward movement space for the working clamp 63. The limiting device 5 is in the second gear, 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 is fully locked to the working clamp 63, the second stage of tensioning is carried out. Figure 5 As shown, the tension is from 0.9 times the design tension force to 1 times the design tension force, and the columnar spring 51 is compressed and deformed, so that the low-retraction anchor 6 and the outer tube 53 and the inner tube 52 go up in parallel, and the low-retraction anchor 6 is 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 force reaches 0.9 times the design tension force, the compression of the columnar spring 51 is very small and can be basically ignored.

[0051] Step 6: When the tensioning force applied by the tensioning jack 3 reaches the designed tensioning force, Figure 6 As shown, the outer ring 62 is rotated and tightened (specifically, the worker can put his hand into the reaction support 4 and hold the outer ring 62 to rotate it, or use the twist wrench 8 in Example 2 to rotate it) so that the outer ring 62 is against the concrete member 7, thereby completing the locking of the steel strand 1 by the low retraction anchor 6.

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

[0053] Embodiment 2

[0054] The structural principle of this embodiment is basically the same as that of the first embodiment, except that Figure 7 and Figure 8 As shown, the locking control device of this embodiment also includes a plurality of torque 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 torque wrenches 8 at circumferential intervals are movably connected to the outer wall of the reaction support 4. The torque wrenches 8 radially pass through the sliders 9 and the side walls of the reaction support 4 and are threadedly connected to the sliders 9.

[0055] In this embodiment, the outer wall of the reaction support 4 has a spiral groove 41 extending circumferentially and axially, and the slider 9 can move circumferentially and axially in the spiral groove 41. For example, the slider 9 has a slide post 91 that is clamped in the spiral groove 41 and slides therein, and the rotation direction and helix angle of the spiral groove 41 are the same as the rotation direction and helix angle of the internal thread on the inner wall of the outer ring 62. Preferably, the slider 9 is an arc block extending circumferentially along the outer wall of the reaction support 4, and the inner surface of the arc block is in contact with the outer surface of the side wall of the reaction support 4.

[0056] In normal state, the torque 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, so as not to affect the tensioning construction. When the outer ring 62 is rotated and tightened in the sixth step, the torque wrench 8 can be rotated by itself, and the torque wrench 8 moves radially, and the length of the torque wrench 8 extending into the reaction support 4 becomes longer and contacts the outer wall of the outer ring 62, and all the torque wrenches 8 are tightened, and multiple torque wrenches 8 hold the outer wall of the outer ring 62 tightly. After holding the outer ring 62 tightly, torque is applied by operating the torque wrench 8. Under the guidance 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 rotation direction and helix angle of the spiral groove 41 are the same as the rotation direction and helix angle of the internal thread on the inner wall of the outer ring 62, the pitches of the two are also equal. The outer ring 62 and the torque wrench 8 move downward in a spiral synchronously, and 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, so that the lower end of the outer ring 62 is pressed against the concrete member 7.

[0057] When the outer ring 62 needs to be rotated multiple times, the torque wrench 8 can be loosened to loosen the outer ring 62, so that the torque wrench and the slider 9 move in the opposite direction to reset, and then the torque wrench is tightened to hold the outer ring 62, and then the torque wrench 8 is operated to rotate the outer ring 62 until the outer ring 62 is pressed against the concrete member 7 and the torque wrench cannot be rotated, thereby ensuring the locking effect of the outer ring 62 and reducing the retraction amount of the working clamp 63. Of course, the outer ring 62 can also be rotated by hand to move downward to contact the concrete member 7, and then multiple torque wrenches are used to hold the outer ring 62 tightly and apply torque to tighten.

[0058] Figure 8 As shown, two twist wrenches 8 are arranged circumferentially. According to the actual situation, three or more twist wrenches 8 can be arranged to ensure that multiple twist wrenches 8 can hold the outer ring 62 tightly. Preferably, the end of the twist wrench 8 has an anti-skid pad, and the shape of the anti-skid pad is an arc that adapts 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 with reference to the terms "preferred embodiment", "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0060] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A locking control device for a low-retraction anchor of a large-diameter steel strand, 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 clip sleeved outside the steel strand and inserted into a tapered hole of the anchor plate; characterized in that: The locking control device comprises a reaction support that can pass through the steel strand and is sleeved outside the low retraction anchor, a tensioning jack connected to the reaction support and located above the reaction support, a tool anchor connected to the upper end of the tensioning jack and used to fix the steel strand, and a limiting device that is arranged in the reaction support and sleeved outside the steel strand, and 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 a limiting effect on the upward movement distance of the working clamp, so that the working clamp can be separated from the anchor plate; By operating the limiting device, the limiting device can make the anchor plate move upward so that the anchor plate locks the working clamp, and the limiting device is in the second gear position.

2. The locking control device for the large diameter steel strand low retraction anchor according to claim 1, characterized in that: The limiting device includes an elastic buffer unit fixedly connected to the reaction support, an inner cylinder fixedly connected to the lower end of the elastic buffer unit and located above the working clamp, 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 anchor plate to move upward, and a limiting groove for limiting the upward movement distance of the working clamp 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 so that the anchor plate locks the working clamp, and the limiting device is in the second gear position.

3. The locking control device for the large diameter steel strand low retraction anchor according to claim 2, characterized in that: The elastic buffer unit is a columnar spring whose upper end is fixedly connected to the reaction force bracket, and the upper end of the inner cylinder is fixedly connected to the lower end of the columnar spring.

4. The locking control device for the large diameter steel strand low retraction anchor according to claim 2, characterized in that: 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. The outer thread of the inner cylinder outer wall has the same rotation direction and helix angle as the outer thread of the anchor plate outer wall.

5. The locking control device for the low retraction anchor of large diameter steel strand according to claim 4, characterized in that: A labor-saving rod for rotating the outer cylinder is connected to the side wall of the outer cylinder.

6. The locking control device for the low retraction anchor of large diameter steel strand according to any one of claims 1 to 5, characterized in that: It also includes a plurality of torque wrenches for rotating the outer ring relative to the anchor plate, the outer wall of the reaction force bracket is circular, a plurality of sliders corresponding to the plurality of torque wrenches are movably connected to the outer wall of the reaction force bracket at circumferential intervals, the torque wrenches radially pass through the sliders and the side walls of the reaction force bracket, and are threadedly connected to the sliders; By rotating the torque wrench, the plurality of torque wrenches can move radially to hold the outer wall of the outer ring, and by operating the torque wrench, the slider can move circumferentially and axially on the outer wall of the reaction support, and the outer ring can spirally move on the anchor plate to keep its lower end away from the lower end of the anchor plate.

7. The locking control device for the low retraction anchor of large diameter steel strand according to claim 6, characterized in that: The outer wall of the reaction support is provided with a spiral groove extending circumferentially and axially, and the slider can move circumferentially and axially in the spiral groove. 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.

8. The locking control device for the large diameter steel strand low retraction anchor according to claim 7, characterized in that: The sliding block has a sliding post which is clamped in the spiral groove and slides therein.

9. The locking control device for the large diameter steel strand low retraction anchor according to claim 7, characterized in that: The sliding block is an arc-shaped block extending circumferentially along the outer wall of the reaction force support, and the inner surface of the arc-shaped block is in contact with the outer surface of the side wall of the reaction force support.

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